bcm2835_pinctrl: Probe pre-reloc

The serial drivers now depend on the pinctrl driver to determine whether
they are enabled. That means if a serial device wants to be used pre-reloc,
we also need the pinctrl device pre-reloc.

Adapt the pinctrl driver as well as dts overlay accordingly.

Signed-off-by: Alexander Graf <agraf@suse.de>
diff --git a/arch/arm/dts/bcm283x-uboot.dtsi b/arch/arm/dts/bcm283x-uboot.dtsi
index 8e4231a..21d038a 100644
--- a/arch/arm/dts/bcm283x-uboot.dtsi
+++ b/arch/arm/dts/bcm283x-uboot.dtsi
@@ -20,3 +20,7 @@
 	skip-init;
 	u-boot,dm-pre-reloc;
 };
+
+&gpio {
+	u-boot,dm-pre-reloc;
+};