drm/amdgpu: Remove else after return in 'is_fru_eeprom_supported'

drm/amdgpu: Remove else after return in 'is_fru_eeprom_supported'

Expressions under 'else' branch under case 'CHIP_SIENNA_CICHLID' in
function 'is_fru_eeprom_supported' are executed whenever the expression
in 'if' is False. Otherwise, return from case occurs. Therefore, there
is no need in 'else', and it has been removed.

Fixes the following:

WARNING: else is not generally useful after a break or return
+                               return false;
+                       } else {

Cc: Christian König <christian.koenig@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Srinivasan Shanmugam <srinivasan.shanmugam@amd.com>
Reviewed-by: Guchun Chen <guchun.chen@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>