msm: adsprpc: remove PM vote counter in fastrpc driver

Remove PM vote counter in the fastrpc driver as the system wakeup
events framework will keep track of CPU awake and relax votes from
a specific client and handle it accordingly.

Change-Id: If4828884f7c659e5a45fd40af954d8146e5cfb24
Acked-by: Thyagarajan Venkatanarayanan <venkatan@qti.qualcomm.com>
Acked-by: Maitreyi Gupta <maitreyi@qti.qualcomm.com>
Signed-off-by: Jeya R <jeyr@codeaurora.org>