alarmtimers: Avoid possible null pointer traversal
alarmtimers: Avoid possible null pointer traversal

We don't check if old_setting is non null before assigning it, so
correct this.

CC: Thomas Gleixner <00e4cf8f46a57000a44449bf9dd8cbbcc209fd2a@linutronix.de>
CC: 4fbacc2fa0ffdbb11bf1ad6925b886ebd08dd15f@kernel.org
Signed-off-by: John Stultz <33837adfb53316eae44aad04041e1240088d76fd@linaro.org>

TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,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