S3c24xx SPI controllers both select 'bitbang'

S3c24xx SPI controllers both select 'bitbang'

Tweak Kconfig for the S3C24XX SPI controller drivers.  Both use the bitbang
framework; only one previously said that.  Plus in this case "select" is
the right way to manage that dependency, since folk will not know up front
to enable bitbang in order to even see those S3C drivers in order to enable
them.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>