ASoC: wcd9330: Remove unnecessary check for BG_CLK lock

Having a check whether BG_CLK acquired or not during
RCO enable will prevent callers requesting for RCO
if the lock is acquired in a different context. Thus,
RCO clock will not get turned ON leading to the use-case
failure. Remove the redundant check for the BG_CLK lock.

Change-Id: I1d422dcb4e4627dc86c4f63da79f91cd216ad8ce
Signed-off-by: Phani Kumar Uppalapati <phaniu@codeaurora.org>