tcg/mips: Fix regression caused by typo (copy + paste bug)

cppcheck reports an error:
qemu/tcg/mips/tcg-target.c:1487: error: Invalid number of character (()

The unpatched code won't compile on mips hosts starting with commit
cea5f9a28faa528b6b1b117c9ab2d8828f473fef.

Cc: Blue Swirl <blauwirbel@gmail.com>
Signed-off-by: Stefan Weil <weil@mail.berlios.de>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
