drm/amdgpu: simplify return statement in amdgpu_ras_eeprom_init

Remove the logically dead code in the last return statement of
amdgpu_ras_eeprom_init. The condition res < 0 is redundant since
res is already checked for a negative value earlier. Replace
return res < 0 ? res : 0; with return 0 to improve clarity.

Fixes: 63d4c081 ("drm/amdgpu: Optimize EEPROM RAS table I/O")
Closes: https://scan7.scan.coverity.com/#/project-view/52337/11354?selectedIssue=1602413


Signed-off-by: Dheeraj Reddy Jonnalagadda <dheeraj.linuxdev@gmail.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>