omap2: use OMAP2_32KSYNCT_BASE in place of OMAP24XX_32KSYNCT_BASE

Change users of OMAP24XX_32KSYNCT_BASE to use OMAP2_32KSYNCT_BASE, in
preparation to remove OMAP24XX_32KSYNCT_BASE.  Convert the 32K sync timer
reference in pm.c to use a symbolic constant rather than a magic number.
Remove the OMAP24XX_32KSYNCT_BASE define.

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