Avoid __fastcall conflicting with system definition

In file included from media_driver/agnostic/common/cm/cm_hal_hashtable.cpp:36:
In file included from media_driver/agnostic/common/cm/cm_hal_hashtable.h:29:
In file included from media_driver/agnostic/common/os/mos_os.h:31:
In file included from media_driver/linux/common/os/media_skuwa_specific.h:32:
In file included from media_driver/linux/common/os/linux_shadow_skuwa.h:31:
In file included from /usr/local/include/igdgmm/GmmLib/inc/GmmLib.h:30:
/usr/local/include/igdgmm/inc/portable_compiler.h:33:13: error: '__fastcall' macro redefined [-Werror,-Wmacro-redefined]
    #define __fastcall
            ^
/usr/include/sys/cdefs.h:372:9: note: previous definition is here
 #define __fastcall      __attribute__((__fastcall__))
         ^

Author: jbeich

Source/inc/portable_compiler.h

@@ -30,6 +30,9 @@ OTHER DEALINGS IN THE SOFTWARE.
     #endif
 
     #define __noop
+    #ifdef __fastcall
+        #undef __fastcall
+    #endif
     #define __fastcall
     #if defined __x86_64__
         #define __stdcall       // deprecated for x86-64