ARM64: dts: bcm2835: Fix bcm2837 compatible string

bcm2837-rpi-3-b.dts, its only in-tree user, was overriding it as
"brcm,bcm2837" already.

Fixes: 9d56c22a ("ARM: bcm2835: Add devicetree for the Raspberry Pi 3.")
Cc: Stephen Warren <swarren@wwwdotorg.org>
Signed-off-by: NAndreas Färber <afaerber@suse.de>
Signed-off-by: NEric Anholt <eric@anholt.net>

arch/arm64/boot/dts/broadcom/bcm2837.dtsi

 #include "bcm283x.dtsi"
 
 / {
-	compatible = "brcm,bcm2836";
+	compatible = "brcm,bcm2837";
 
 	soc {
 		ranges = <0x7e000000 0x3f000000 0x1000000>,