ARM: dts: msm: Keep the critical bus resources alive

Add a proxy client driver which can be used to cast a proxy
bandwidth vote during boot up for a critical resource which
is removed at the end of boot. This is required to ensure
that a certain minimum state for a critical resource at the
beginning of boot up before the clients have probed and voted
for required state.

Change-Id: Ia496ec20c88fa6e836bcc6694d7bc37556bf485a