drm/amd/display: Fix potential null pointer dereference in dc_dmub_srv

Fixes potential null pointer dereference warnings in the
dc_dmub_srv_cmd_list_queue_execute() and dc_dmub_srv_is_hw_pwr_up()
functions.

In both functions, the 'dc_dmub_srv' variable was being dereferenced
before it was checked for null. This could lead to a null pointer
dereference if 'dc_dmub_srv' is null. The fix is to check if
'dc_dmub_srv' is null before dereferencing it.

Thus moving the null checks for 'dc_dmub_srv' to the beginning of the
functions to ensure that 'dc_dmub_srv' is not null when it is
dereferenced.

Found by smatch & thus fixing the below:
drivers/gpu/drm/amd/amdgpu/../display/dc/dc_dmub_srv.c:133 dc_dmub_srv_cmd_list_queue_execute() warn: variable dereferenced before check 'dc_dmub_srv' (see line 128)
drivers/gpu/drm/amd/amdgpu/../display/dc/dc_dmub_srv.c:1167 dc_dmub_srv_is_hw_pwr_up() warn: variable dereferenced before check 'dc_dmub_srv' (see line 1164)

Fixes: 028bac583449 ("drm/amd/display: decouple dmcub execution to reduce lock granularity")
Fixes: 65138eb72e1f ("drm/amd/display: Add DCN35 DMUB")
Cc: JinZe.Xu <[email protected]>
Cc: Hersen Wu <[email protected]>
Cc: Josip Pavic <[email protected]>
Cc: Roman Li <[email protected]>
Cc: Qingqing Zhuo <[email protected]>
Cc: Harry Wentland <[email protected]>
Cc: Rodrigo Siqueira <[email protected]>
Cc: Aurabindo Pillai <[email protected]>
Cc: Tom Chung <[email protected]>
Signed-off-by: Srinivasan Shanmugam <[email protected]>
Reviewed-by: Tom Chung <[email protected]>
Signed-off-by: Alex Deucher <[email protected]>

0 files changed, 0 insertions, 0 deletions