msm: gdsc: Collapse core memories during GDSC collapse on 8x26

When a core is power-collapsed the contents of its internal
memories need not be retained. Collapse the memories to
save some additional power.

This is accomplished by specifying a list of clock domains
which have collapsible memories. The GDSC driver will iterate
over each of these clocks and call clk_set_flags() on each of
them to collapse and restore power, as appropriate.

Change-Id: I5c2625f955b25e55ae63d25da533bc4a26ad8422
Signed-off-by: Matt Wagantall <mattw@codeaurora.org>