MIPS: Add missing includes to gic.h

The gic.h header uses bitmaps and NR_CPUS, and should therefore include
linux/bitmap.h and linux/threads.h. This is in preparation for use of
this header in a subsequent commit from a C file which doesn't already
include those headers.
Signed-off-by: NPaul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6357/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

arch/mips/include/asm/gic.h

@@ -11,6 +11,9 @@
 #ifndef _ASM_GICREGS_H
 #define _ASM_GICREGS_H
 
+#include <linux/bitmap.h>
+#include <linux/threads.h>
+
 #undef	GICISBYTELITTLEENDIAN
 
 /* Constants */