ARM: OMAP4: Bypass the clock check.

Second reason of OMAP4 boot failure on 2.6.31.rc6, the UART
platform data is not getting registered to kernel.
Registration was failing because of clock check failure in
omap_serial_init().
Below patch fix the same.

OMAP4 clock framework patches are still getting discussed on mailing
list so till then we need this.

Signed-off-by: Syed Rafiuddin <rafiuddin.syed@ti.com>
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>