msm: acpuclock-krait: Add support for HFPLL lock detect bit polling

Some recent devices have a lock detect bit that can be used to
determine when the HFPLL frequency has stabilized. Add optional
support for polling this bit instead of delaying pessimistically
for 60us.

Change-Id: I38bb0c98e36f66fc5efadf9189dbe817f648a972
Signed-off-by: Matt Wagantall <mattw@codeaurora.org>