OMAP4: clockdomain: Add wkup/sleep dependency support

Add OMAP4 platform specific implementation to support clkdm
wkup and sleep dependencies a.k.a static dependencies.

Signed-off-by: Rajendra Nayak <rnayak@ti.com>
[paul@pwsan.com: removed comment about PRM; zero-prefixed STATICDEP
 register offset; fixed loop termination condition in
 omap4_clkdm_clear_all_wkup_sleep_deps(); thanks to Kevin Hilman for finding
 and helping fix this bug]
Cc: Kevin Hilman <khilman@deeprootsystems.com>
Signed-off-by: Paul Walmsley <paul@pwsan.com>