gpu: nvgpu: unit: increase coverage and docs for mm

For common.mm subunits, this patch:
- adds extra test cases for some lesser used APIs
- updates SWUTS to add several functions to Targets fields.

JIRA NVGPU-3510

Change-Id: I350fbe0927472e1a07385a8cf87e0f0a8bbb6a8c
Signed-off-by: Nicolas Benech <nbenech@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/c/linux-nvgpu/+/2280067
Reviewed-by: svc-mobile-coverity <svc-mobile-coverity@nvidia.com>
Reviewed-by: Vijayakumar Subbu <vsubbu@nvidia.com>
Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com>
GVS: Gerrit_Virtual_Submit
Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>

userspace/units/mm/as/as.h

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2019, NVIDIA CORPORATION.  All rights reserved.
+ * Copyright (c) 2019-2020, NVIDIA CORPORATION.  All rights reserved.
  *
  * Permission is hereby granted, free of charge, to any person obtaining a
  * copy of this software and associated documentation files (the "Software"),
@@ -113,7 +113,8 @@ int test_init_mm(struct unit_module *m, struct gk20a *g, void *args);
  *
  * Test Type: Feature
  *
- * Targets: gk20a_as_alloc_share, gk20a_as_release_share
+ * Targets: gk20a_as_alloc_share, gk20a_as_release_share,
+ * gk20a_vm_release_share, gk20a_from_as
  *
  * Input:
  * - The test_init_mm must have been executed
@@ -147,4 +148,24 @@ int test_init_mm(struct unit_module *m, struct gk20a *g, void *args);
  */
 int test_as_alloc_share(struct unit_module *m, struct gk20a *g, void *args);
 
+/**
+ * Test specification for: test_gk20a_from_as
+ *
+ * Description: Simple test to check gk20a_from_as.
+ *
+ * Test Type: Feature
+ *
+ * Targets: gk20a_from_as
+ *
+ * Input: None
+ *
+ * Steps:
+ * - Call gk20a_from_as with an 'as' pointer and ensure it returns a
+ *   pointer on g.
+ *
+ * Output: Returns PASS if the steps above were executed successfully. FAIL
+ * otherwise.
+ */
+int test_gk20a_from_as(struct unit_module *m, struct gk20a *g, void *args);
+
 #endif /* UNIT_MM_AS_H */