linux-google-crosshatch-mainline: update kernel to 5.3-rc5
This rebases the Pixel 3 XL patches on top of Linux 5.3-rc5.
Also enabled more kernel modules related to modem, and applied Bjorn Andersson's patch for resetting the UFS memory.
See https://gitlab.com/postmarketOS/pmaports/issues/153 for more information.
[ci:skip-build] because kernel takes more than one hour to build.
I've built this locally and confirmed it boots:
/ # cat /proc/version
Linux version 5.3.0-rc5 (pmos@theodora) (gcc version 8.3.0 (Alpine 8.3.0)) #1-google-crosshatch-mainline SMP PREEMPT Sun Aug 25 15:34:25 UT