drm/amd/pm: Fix mode2 reset ACK handling on aldebaran v2

drm/amd/pm: Fix mode2 reset ACK handling on aldebaran v2

aldebaran_mode2_reset() sends a mode2 reset message and waits for
an acknowledgment from the SMU.

The current ACK handling is incorrect.

The wait loop runs only when ret is -ETIME. But after a successful
async send, ret is 0. Because of this, the loop is skipped and the
code does not wait for the reset acknowledgment.

Also, the code checks for ret != 1 after calling
smu_msg_wait_response(). However, smu_msg_wait_response() returns
0 on success and negative error codes on failure. So checking
against 1 is wrong.

Return -EOPNOTSUPP when the firmware does not support this reset
message.

Fix this by setting ret to -ETIME before entering the wait loop,
checking for ret != 0 after getting the SMU response, and returning
-EOPNOTSUPP when the firmware does not support the message.

v2:
- Update ACK check to use ret != 0 instead of ret != 1, since
  smu_msg_wait_response() returns 0 on success (Feifei)
- Remove unnecessary handling for ret == 0

Fixes: e42569d02acb ("drm/amd/pm: Modify mode2 msg sequence on aldebaran")
Reported-by: Dan Carpenter <error27@gmail.com>
Cc: Feifei Xu <Feifei.Xu@amd.com>
Cc: Lijo Lazar <lijo.lazar@amd.com>
Cc: Hawking Zhang <Hawking.Zhang@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Christian König <christian.koenig@amd.com>
Signed-off-by: Srinivasan Shanmugam <srinivasan.shanmugam@amd.com>
Reviewed-by: Feifei Xu <Feifei.Xu@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>