ARM: dts: BCM5301X: Fix Linksys EA9500 partitions

Partitions are basically fixed indeed but firmware ones don't have
hardcoded function ("firmware" vs "failsafe"). Actual function depends
on bootloader configuration. Use a proper binding for that.

While at it fix numbers formatting to avoid:
arch/arm/boot/dts/bcm47094-linksys-panamera.dt.yaml: partitions: 'partition@1F00000' does not match any of the regexes: '^partition@[0-9a-f]+$', 'pinctrl-[0-9]+'
        From schema: Documentation/devicetree/bindings/mtd/partitions/linksys,ns-partitions.yaml

Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>