ARM: omap1: move 32k counter from plat-omap to mach-omap1

omap2 stopped using this code with commit 8d39ff3d ("ARM: OMAP2+:
Remove unused legacy code for timer"), so just move it to mach-omap1 now,
along with the other half of that driver.

Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>