Parenthesis fix in include/asm-mips/gic.h

Signed-off-by: Mariusz Kozlowski <m.kozlowski@tuxland.pl>
Cc: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>