linux-postmarketos-qcom-sm8250: upgrade to 6.11.0

changes in kernel:

1. upgrade to 6.11.0
2. fix pogo keyboard issue (disconect intermittenly).

changes in device-xiaomi-elish:

1. drop pd-mapper because pd-mapper has gone into kernel module
2. add hexagonrpcd to support accelerometer and ambient light sensor

changes in firmware-xiaomi-elish:

1. add hexagonfs files
2. add myself as maintainer

issues: pogo keyboard blocks sensors, sensors work normally when disable pogo keyboard.

device/testing/device-xiaomi-elish/81-libssc-xiaomi-elish.rules

+# iio-sensor-proxy with libssc: accelerometer mount matrix
+SUBSYSTEM=="misc", KERNEL=="fastrpc-*", ENV{ACCEL_MOUNT_MATRIX}+="-1, 0, 0; 0, -1, 0; 0, 0, -1"