tegra: platform: dce: use mutex_lock API properly

Improper use of mutex_lock API is leading to below crash with
rt kernel, this patch fixes the below crash.

dce: dce_req_boot_irq_sync:70   Waiting on dce fw to boot...
------------[ cut here ]------------
DEBUG_LOCKS_WARN_ON(rt_mutex_owner(lock) != current)
WARNING: CPU: 0 PID: 126 at /dvs/git/dirty/git-master_modular/out/
aarch64-arm64-tegra_defconfig-rt_patches-debug-extmod_ubuntu18.04_aarch64
-extmod_linux_x86_64/kernel/src-rt/kernel-5.10/kernel/locking/
rtmutex-debug.c:47 debug_rt_mutex_unlock+0x5c/0x68
 Modules linked in:
 CPU: 0 PID: 126 Comm: dce_worker_thre Not tainted 5.10.17-rt32-tegra #2
 Hardware name: t234pre_si (DT)
 pstate: 00800089 (nzcv daIf -PAN +UAO -TCO BTYPE=--)
 pc : debug_rt_mutex_unlock+0x5c/0x68
 lr : debug_rt_mutex_unlock+0x5c/0x68
 sp : ffff8000137fbc90
 x29: ffff8000137fbc90 x28: 0000000000000000
 x27: 0000000000000000 x26: ffff800012241180
 x25: ffff000082b7e090 x24: ffff800010e781d0
 x23: 0000000000000000 x22: ffff8000137fbd18
 x21: ffff8000137fbd08 x20: 0000000000000000
 x19: ffff000082b7e0b8 x18: ffffffffffffffff
 x17: 00000000000000c0 x16: fffffe0001eadf40
 x15: ffff800011e6f988 x14: ffff8000937fb817
 x13: ffff8000137fb825 x12: 2065756c61562020
 x11: 0000000005f5e0ff x10: ffff8000137fb770
 x9 : ffff8000137fbc90 x8 : 4e5241575f534b43
 x7 : 000000000000001f x6 : ffff80001224a65c
 x5 : 00000000ffffe163 x4 : 00000000ffffe163
 x3 : ffff800011f3ba50 x2 : 0000000100000001
 x1 : 0e62cf1b356d1e00 x0 : 0000000000000000
 Call trace:
  debug_rt_mutex_unlock+0x5c/0x68
  rt_mutex_slowunlock+0x38/0x98
  rt_mutex_unlock+0x5c/0x98
  __rt_mutex_unlock+0x20/0x30
  _mutex_unlock+0x20/0x30
  dce_worker_thread_wait+0x88/0x300
  dce_wait_boot_complete+0x74/0x118
  dce_worker+0x24/0x1c8
  dce_thread_proxy+0x20/0x30
  kthread+0x194/0x1a0
  ret_from_fork+0x10/0x18
 ---[ end trace 0000000000000001 ]---

JIRA ESLC-5710

Signed-off-by: Manish Bhardwaj <mbhardwaj@nvidia.com>
Change-Id: I0a67b4792515ca8212dc4a3b34ead5bde9f94f49
Reviewed-on: https://git-master.nvidia.com/r/c/linux-t23x/+/2499983
Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>
Reviewed-by: Arun Swain <arswain@nvidia.com>
Reviewed-by: svcacv <svcacv@nvidia.com>
Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com>
GVS: Gerrit_Virtual_Submit

drivers/platform/tegra/dce/dce-worker.c

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2019-2020, NVIDIA CORPORATION.  All rights reserved.
+ * Copyright (c) 2019-2021, NVIDIA CORPORATION.  All rights reserved.
  *
  * This program is free software; you can redistribute it and/or modify it
  * under the terms and conditions of the GNU General Public License,
@@ -91,8 +91,6 @@ void dce_worker_thread_wait(struct tegra_dce *d,
 	if (new_state == STATE_DCE_WORKER_BOOT_WAIT)
 		timeout_val_ms = 1000;
 
-	dce_mutex_unlock(&w->lock);
-
 	ret = DCE_COND_WAIT_INTERRUPTIBLE(&w->cond,
 				dce_worker_wakeup_cond(d),
 				timeout_val_ms);