ANDROID: smp: fix preprocessor conditional warning

This fixes the following warning:
kernel/smp.c: In function ‘wake_up_all_idle_cpus’:
kernel/smp.c:961:5: warning: "CONFIG_SUSPEND" is not defined, evaluates to 0 [-Wundef]
 #if CONFIG_SUSPEND
     ^~~~~~~~~~~~~~

Bug: 183339614
Fixes: fc005b3c (ANDROID: fix 0-day build-break for non-GKI)
Reported-by: kernelci.org bot <bot@kernelci.org>
Signed-off-by: Carlos Llamas <cmllamas@google.com>
Change-Id: Ieeff7c0a49237e117e93e653b8f1a3e2d63f3f65