arch/arm/Kconfig: remove one to many l's in the word.

The patch below removes an extra "l" in the word.

Signed-off-by: Justin P. Mattock <justinmattock@gmail.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>