bcm2708_pinctrl: select PINCONF and PINMUX

Also don't default y as it is select by MACH_BCM2708. Suggested by
Stephen Warren.

Signed-off-by: Chris Boot <bootc@bootc.net>

drivers/pinctrl/Kconfig

@@ -140,7 +140,8 @@ config PINCTRL_COH901
 config PINCTRL_BCM2708
 	bool "Broadcom BCM2708 GPIO pin controller driver"
 	depends on MACH_BCM2708 && OF
-	default y if MACH_BCM2708
+	select PINMUX
+	select PINCONF
 
 source "drivers/pinctrl/spear/Kconfig"