mailbox: Add support for bcm74110

The bcm74110 mailbox driver is used to communicate with
a co-processor for various power management and firmware
related tasks.

Signed-off-by: Justin Chen <justin.chen@broadcom.com>
Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
Tested-by: Florian Fainelli <florian.fainelli@broadcom.com>
Signed-off-by: Jassi Brar <jassisinghbrar@gmail.com>

drivers/mailbox/Kconfig

@@ -350,4 +350,14 @@ config CIX_MBOX
           is unidirectional. Say Y here if you want to use the CIX Mailbox
           support.
 
+config BCM74110_MAILBOX
+	tristate "Brcmstb BCM74110 Mailbox"
+	depends on ARCH_BRCMSTB || COMPILE_TEST
+	default ARCH_BRCMSTB
+	help
+	  Broadcom STB mailbox driver present starting with brcmstb bcm74110
+	  SoCs. The mailbox is a communication channel between the host
+	  processor and coprocessor that handles various power management task
+	  and more.
+
 endif

drivers/mailbox/Makefile

@@ -74,3 +74,5 @@ obj-$(CONFIG_QCOM_IPCC)		+= qcom-ipcc.o
 obj-$(CONFIG_THEAD_TH1520_MBOX)	+= mailbox-th1520.o
 
 obj-$(CONFIG_CIX_MBOX)	+= cix-mailbox.o
+
+obj-$(CONFIG_BCM74110_MAILBOX)	+= bcm74110-mailbox.o