omap2: standardize clock.h enable_reg/enable_bit order

A few of the clock definitions in mach-omap2/clock.h list the
.enable_bit member before .enable_reg.  This fixes those to conform
with the order used in the rest of the file.

Signed-off-by: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>