gk20a_ltc_init_comptags and gk20a_ltc_clear_comptags are defined
in ltc_gk20a.c, gm20b has its own init/clear functions, so remove
these two from ltc_common.c
change nvhost_allocator_init to gk20a_allocator_init, this is a
left-over after rebase, just like the above 2 function definitions,
so fix it.
Change-Id: I829639dd7fee9110dd65d5df7d7f0f8fe5fca6c1
Signed-off-by: Bo Yan <byan@nvidia.com>