spi: spi_s3c24xx must initialize num_chipselect

The SPI core now expects num_chipselect to be set correctly as due to added
checks on the chip being selected before an transfer is allowed.  This patch
adds a num_cs field to the platform data which needs to be set correctly
before adding the SPI platform device.

Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>