clk: qcom: gdsc: Check gdsc enable status using poll_gdsc_status

The generic readl_poll family of functions has been showing inconsistent
behaviour. Instead of relying on those for checking status of the GDSCR,
instrument and use a new macro to do the same.

Change-Id: I6b2b20f46e3f9bdc2b1fcb18fc0dfd2abbb2cc33
Signed-off-by: Pushkar Joshi <pushkarj@codeaurora.org>