[MIPS] setup.c: do not inline functions

There's no point to inline any functions in setup.c. Let's GCC
doing its job, it's good enough for that now.

Signed-off-by: Franck Bui-Huu <vagabon.xyz@gmail.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>