ARM: OMAP: Register the 24xx McSPI device

Register the 24xx McSPI device as an OMAP2 platform device.  The driver
module and Kconfig option were merged already some time ago.

Signed-off-by: Juha Yrjola <juha.yrjola@solidboot.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>