arm64: dts: qcom: qcm6490-fairphone-fp5: Add touchscreen node

Add a node for the GT9897 touchscreen found on this smartphone connected
via SPI.

Reviewed-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
Signed-off-by: Luca Weiss <luca.weiss@fairphone.com>
Link: https://lore.kernel.org/r/20250312-fp5-touchscreen-v2-1-4bed270e0065@fairphone.com


Signed-off-by: Bjorn Andersson <andersson@kernel.org>