drm/amd/display: Remove the unused function dmub_outbox_irq_info_funcs

The function dmub_outbox_irq_info_funcs is defined in the
irq_service_dcn201.c file, but not called elsewhere, so remove this
unused function.

drivers/gpu/drm/amd/amdgpu/../display/dc/irq/dcn201/irq_service_dcn201.c:139:43: warning: unused variable 'dmub_outbox_irq_info_funcs'.

Link: https://bugzilla.openanolis.cn/show_bug.cgi?id=3520Reported-by: NAbaci Robot <abaci@linux.alibaba.com>
Signed-off-by: NJiapeng Chong <jiapeng.chong@linux.alibaba.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/irq/dcn201/irq_service_dcn201.c

@@ -136,11 +136,6 @@ static const struct irq_source_info_funcs vupdate_no_lock_irq_info_funcs = {
 	.ack = NULL
 };
 
-static const struct irq_source_info_funcs dmub_outbox_irq_info_funcs = {
-	.set = NULL,
-	.ack = NULL
-};
-
 #undef BASE_INNER
 #define BASE_INNER(seg) DMU_BASE__INST0_SEG ## seg