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: NAlexander Graf <agraf@suse.de>

arch/arm/dts/bcm283x-uboot.dtsi

@@ -20,3 +20,7 @@
 	skip-init;
 	u-boot,dm-pre-reloc;
 };
+
+&gpio {
+	u-boot,dm-pre-reloc;
+};

drivers/pinctrl/broadcom/pinctrl-bcm283x.c

@@ -148,5 +148,6 @@ U_BOOT_DRIVER(pinctrl_bcm283x) = {
 	.of_match	= of_match_ptr(bcm2835_pinctrl_id),
 	.priv_auto_alloc_size = sizeof(struct bcm283x_pinctrl_priv),
 	.ops		= &bcm283x_pinctrl_ops,
-	.probe		= bcm283x_pinctl_probe
+	.probe		= bcm283x_pinctl_probe,
+	.flags		= DM_FLAG_PRE_RELOC,
 };