dt-bindings: net: qcom,ipa: add some compatible strings

Add existing supported platform "qcom,sc7180-ipa" to the set of IPA
compatible strings.  Also add newly-supported "qcom,sdx55-ipa",
"qcom,sc7280-ipa".

Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>