ARM: dts: qcom: fix flash node naming for RB3011

rename node to comply with dt-schema

Fix warning:
arch/arm/boot/dts/qcom-ipq8064-rb3011.dt.yaml: s25fl016k@0: $nodename:0: 's25fl016k@0' does not match '^flash(@.*)?$'
	From schema: Documentation/devicetree/bindings/mtd/jedec,spi-nor.yaml

Signed-off-by: David Heidelberg <david@ixit.cz>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20211020204145.235050-1-david@ixit.cz