OMAP: clockdomain: Remove redundant call to pwrdm_wait_transition()

The call to pwrdm_wait_transition() in clkdm_clk_enable()
is redundant since the function pwrdm_clkdm_state_switch()
which is called next also does the same thing.

Signed-off-by: Vaibhav Bedia <vaibhav.bedia@ti.com>
Signed-off-by: Paul Walmsley <paul@pwsan.com>