Revert "ARM: gic: Add flag to select 8625 QGIC2 back to back read/write workaround"

This reverts commit cfe3e2b6.
Dropping support for MSM8625.

Change-Id: Ic2a5f5ec8d1a4e96d58f36e08f974752db6173c5
Signed-off-by: Abhimanyu Kapur <abhimany@codeaurora.org>