ARM: cpu hotplug: remove majority of cache flushing from platforms

Remove the majority of cache flushing calls from the individual platform
files.  This is now handled by the core code.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
Revert "ARM: dts: msm8974: Allow power collapse as minimum l2 gdhs mode"

This reverts commit 6e5d1ca34ab785bab296ceb45c4f6b1ba1cc092d.