OMAP1: clock: some cleanup

Convert most of the magic numbers in mach-omap1/clock_data.c to use
macros.  Clean up a few comments to conform with Documentation/CodingStyle.
Mark the current clkops_uart as being OMAP16xx-only, and add some comments
to indicate that it does not belong there, for future cleanup.

This patch should not cause any functional changes.

Signed-off-by: Paul Walmsley <paul@pwsan.com>