OMAP2xxx: clock: fix interface clocks and clockdomains for modules in the WKUP domain

The parent of the interface clocks for GPTIMER1, MPU_WDT,
SYNCTIMER_32K, SCM, WDT1, and the ICR (2430 only) were all listed as
being l4_ck.  This isn't accurate; these modules exist inside the WKUP
domain, and the interface clock to these modules runs at the SYS_CLK
rate rather than the CORE L4 rate.

So, create a new clock "wu_l4_ick", similar to the OMAP3
"wkup_l4_ick", that serves as the parent for these clocks.

Also, these clocks were listed as existing inside core_l4_clkdm;
wkup_clkdm is probably more accurate.

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