MIPS: Optimize current_cpu_type() for better code.
o Move current_cpu_type() to a separate header file
o #ifdefing on supported CPU types lets modern GCC know that certain
code in callers may be discarded ideally turning current_cpu_type() into
a function returning a constant.
o Use current_cpu_type() rather than direct access to struct cpuinfo_mips.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Cc: Steven J. Hill <Steven.Hill@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/5833/