msm: pil-q6v4: Change modem shutdown sequence

Existed sequence:
	axi_bus_halt(modem)
	pas_shutdown(modem)
	axi_bus_halt(modem_fw)
	pas_shutdown(modem_fw)

With the above sequence some outstanding transactions from Modem FW
when the clock reset happens, will cause a bus hang leading to a system
reset.

Do bus axi port halt for modem SW and modem FW together before making TZ
calls for either modem SW/FW reset. New sequence would be as below.

New sequence:
	axi_bus_halt(modem)
	axi_bus_halt(modem_fw)
	pas_shutdown(modem)
	pas_shutdown(modem_fw)

CR-Fixed: 504698
Change-Id: I40ad1116f96b0d77ee3b6be29f3295cc7ae171a1
Signed-off-by: Tirupathi Reddy <tirupath@codeaurora.org>
Merge "msm: pil-q6v4: Change modem shutdown sequence"