drm/radeon: fix pptable.h portability

The following isn't compatible with gcc 2.x:

pragma pack(push, 1)
...
pragma pack(pop)

replace with:

pragma pack(1)
...
pragma pack()

bug:
https://bugzilla.kernel.org/show_bug.cgi?id=67961

Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/radeon/pptable.h

@@ -23,7 +23,7 @@
 #ifndef _PPTABLE_H
 #define _PPTABLE_H
 
-#pragma pack(push, 1)
+#pragma pack(1)
 
 typedef struct _ATOM_PPLIB_THERMALCONTROLLER
 
@@ -677,6 +677,6 @@ typedef struct _ATOM_PPLIB_PPM_Table
       ULONG  ulTjmax;
 } ATOM_PPLIB_PPM_Table;
 
-#pragma pack(pop)
+#pragma pack()
 
 #endif