[MIPS] Remove unused rm9k_cpu_irq_disable()
[MIPS] Remove unused rm9k_cpu_irq_disable()

rm9k_cpu_irq_disable() is unused since commit
1603b5aca4f15b34848fb5594d0c7b6333b99144.  Remove it.

Signed-off-by: Atsushi Nemoto <80aeab2fcc576fb9134b563f36af765199d49e90@mba.ocn.ne.jp>
Signed-off-by: Ralf Baechle <92f48d309cda194c8eda36aa8f9ae28c488fa208@linux-mips.org>

KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs