Staging: Kconfig for ARCH=arm,8300, cris

The new Kconfig option to build "staging" drivers (code in
drivers/staging/) is seen in all except three architectures (arm, h8300,
cris), because in these cases arch/$ARCH/Kconfig does NOT source
drivers/Kconfig.

This patch adds the source "drivers/staging/Kconfig" to
arch/$ARCH/Kconfig for these three exceptional cases.

Signed-off-by: Duncan Haldane <duncan_h@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>