arm64: dts: qcom: sc7280: Add 'piglin' to the crd-r3 compatible strings

With newer bootloader versions the crd-r3 (aka CRD 1.0 and 2.0) is
identified as a 'piglin' board (like the IDP2 board), instead of 'hoglin'
Add the compatible strings 'google,piglin-rev{3,4}'. The hoglin entries
are kept to make sure the board keeps booting with older bootloader
versions.

The compatible string 'google,piglin' (without revision information) is
still used by the IDP2 board, which is not expected to evolve further.

Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
Reviewed-by: Rajendra Nayak <quic_rjendra@quicinc.com>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20220316172814.v1.2.Ib0fbb7e5218201c81a2d064ff13c9bc1b0863212@changeid