PCI: brcmstb: PCIE_BRCMSTB depends on ARCH_BRCMSTB

Have PCIE_BRCMSTB depend on ARCH_BRCMSTB.  Also set the default value to
ARCH_BRCMSTB.

Link: https://lore.kernel.org/r/20200911175232.19016-2-james.quinlan@broadcom.comSigned-off-by: Jim Quinlan <jquinlan@broadcom.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Acked-by: Florian Fainelli <f.fainelli@gmail.com>

drivers/pci/controller/Kconfig

@@ -270,9 +270,10 @@ config VMD
 
 config PCIE_BRCMSTB
 	tristate "Broadcom Brcmstb PCIe host controller"
-	depends on ARCH_BCM2835 || COMPILE_TEST
+	depends on ARCH_BRCMSTB || ARCH_BCM2835 || COMPILE_TEST
 	depends on OF
 	depends on PCI_MSI_IRQ_DOMAIN
+	default ARCH_BRCMSTB
 	help
 	  Say Y here to enable PCIe host controller support for
 	  Broadcom STB based SoCs, like the Raspberry Pi 4.