arm64: mm: fix the function name in comment of cpu_do_switch_mm

Fix the function name of comment of cpu_do_switch_mm,
because cpu_do_switch_mm is the correct name.
Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

arch/arm64/mm/proc.S

@@ -150,7 +150,7 @@ ENDPROC(cpu_do_resume)
 #endif
 
 /*
- *	cpu_switch_mm(pgd_phys, tsk)
+ *	cpu_do_switch_mm(pgd_phys, tsk)
  *
  *	Set the translation table base pointer to be pgd_phys.
  *