MFGPT: move clocksource menu

Move the CS5535 MFGPT hrtimer kconfig option to be with the other MFGPT
options.  This makes it easier to find and also removes it from the main
"Device Drivers" menu, where it should not have been.

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Acked-by: Andres Salomon <dilinger@collabora.co.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>