drivers: mailbox: allow active votes to be sent using wake TCS

When a TCS mailbox does not have explicit TCSes to send active mode
commands (AMC), use wake TCS to send the active votes. Any TCS can be
configured to send active mode votes, but using the TCS in active mode
complicates TCS slot allocation.

By explicitly requesting RPMH_AWAKE_STATE, active mode request can be
made for a resource through a DRV that does not have a dedicated TCS in
AMC mode. A WAKE TCS will be used to send these active requests and the
resource is stored as a wake value. The wake vote will be sent everytime
the RSC wakes up from sleep, unless the invalidate command is sent to
the mailbox driver.

Change-Id: I2e7435d1451657f18b4331b02217750107fe9511
Signed-off-by: Lina Iyer <ilina@codeaurora.org>