MAINTAINERS: Update timer related entries
MAINTAINERS: Update timer related entries

Bring the existing file list up to date and add a new entry for
timekeeping and ntp. Assign John Stultz to this new entry so he gets
all the blame :)

Signed-off-by: Thomas Gleixner <00e4cf8f46a57000a44449bf9dd8cbbcc209fd2a@linutronix.de>
Cc: John Stultz <2dbbc9a029f6af74f2c2786ce8fa25d932fcaf8c@us.ibm.com>

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