MAINTAINERS: update ssbi patterns

Commit 45fcac1a

 ("mfd: Move ssbi driver into drivers/mfd") move the
files, update the patterns.

Signed-off-by: Joe Perches <joe@perches.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Samuel Ortiz <sameo@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>