soc: qcom: Add QTI Mailbox Protocol driver

QTI Mailbox Protocol (QMP) is a lightweight communication
driver that fits in to the mailbox framework. Each mailbox
supports up to one channel. This channel can send and receive
one message at a time.

Change-Id: I944d001600c1f0acb8cd602040b90685f80713a7
Signed-off-by: Chris Lew <clew@codeaurora.org>
diff --git a/drivers/mailbox/Makefile b/drivers/mailbox/Makefile
index 0a01d79..3c811d3 100644
--- a/drivers/mailbox/Makefile
+++ b/drivers/mailbox/Makefile
@@ -31,3 +31,5 @@
 obj-$(CONFIG_BCM_PDC_MBOX)	+= bcm-pdc-mailbox.o
 
 obj-$(CONFIG_QTI_RPMH_MBOX)	+= qti-tcs.o
+
+obj-$(CONFIG_MSM_QMP)	+= msm_qmp.o