msm: dma: Toggle adm_pclk along with adm_clk

Previously we just left the pclk in whatever state it was in at boot.
Instead, turn it off and on at the same time that we turn the regular
clock on and off.

Signed-off-by: Jeff Ohlstein <johlstei@codeaurora.org>
Signed-off-by: David Brown <davidb@codeaurora.org>