arm64: kernel: Update kerneldoc for cpu_suspend() rename

Commit af391b15 ("arm64: kernel: rename __cpu_suspend to keep it
aligned with arm") renamed cpu_suspend() to arm_cpuidle_suspend(), but
forgot to update the kerneldoc header.

Fixes: af391b15 ("arm64: kernel: rename __cpu_suspend to keep it aligned with arm")
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

arch/arm64/kernel/cpuidle.c

@@ -30,7 +30,7 @@ int arm_cpuidle_init(unsigned int cpu)
 }
 
 /**
- * cpu_suspend() - function to enter a low-power idle state
+ * arm_cpuidle_suspend() - function to enter a low-power idle state
  * @arg: argument to pass to CPU suspend operations
  *
  * Return: 0 on success, -EOPNOTSUPP if CPU suspend hook not initialized, CPU