drm/amd/pm: suppress compile warning about possible unaligned accesses

Suppress the following compile warning:
   In file included from drivers/gpu/drm/amd/amdgpu/../pm/swsmu/smu13/smu_v13_0_0_ppt.c:39:
>> drivers/gpu/drm/amd/amdgpu/../pm/inc/smu_v13_0_0_pptable.h:194:39:
warning: field overdrive_table within 'struct smu_13_0_0_powerplay_table' is
less aligned than 'struct smu_13_0_0_overdrive_table' and is usually due to
'struct smu_13_0_0_powerplay_table' being packed,
which can lead to unaligned accesses [-Wunaligned-access]
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Evan Quan <evan.quan@amd.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/pm/inc/smu_v13_0_0_pptable.h

@@ -22,6 +22,8 @@
 #ifndef SMU_13_0_0_PPTABLE_H
 #define SMU_13_0_0_PPTABLE_H
 
+#pragma pack(push, 1)
+
 #define SMU_13_0_0_TABLE_FORMAT_REVISION 15
 
 //// POWERPLAYTABLE::ulPlatformCaps
@@ -194,7 +196,8 @@ struct smu_13_0_0_powerplay_table
     struct smu_13_0_0_overdrive_table overdrive_table;
     uint8_t padding1;
     PPTable_t smc_pptable; //PPTable_t in driver_if.h
-} __attribute__((packed));
+};
 
+#pragma pack(pop)
 
 #endif