ARM: OMAP2+: powerdomain: Get rid off duplicate pwrdm_clkdm_state_switch() API

With patch 'ARM: OMAP2+: powerdomain: Wait for powerdomain transition
in pwrdm_state_switch()', the pwrdm_clkdm_state_switch() API becomes
duplicate of pwrdm_state_switch().

Get rid off duplicate pwrdm_clkdm_state_switch() and update the
users of it with pwrdm_state_switch()

Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Cc: Rajendra Nayak <rnayak@ti.com>
Cc: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Paul Walmsley <paul@pwsan.com>