linux-postmarketos-exynos4: update to 5.15-rc2

With the added patches charging works, and battery percentage is reported correctly on i9300/i9305. If the phone reaches ~2 % battery it is turned off automatically (at least on phosh). I have also removed the warning about hardware issues with mainline, since the only theory is that a deeply discharged battery might have caused it, and with these fixes is should be harder to end up in that situation.

Charging seem to be a bit quirky, it can stop unexpectedly at a random percentage, and ssh'ing into the phone over usb does not seem to be possible when it is charging. When attaching cable, dmesg on computer shows:

[ 1117.915907] usb 1-14: USB disconnect, device number 10
[ 1117.916079] cdc_ether 1-14:1.0 enp0s20f0u14: unregister 'cdc_ether' usb-0000:00:14.0-14, CDC Ethernet Device
[ 1120.841840] usb 1-14: new high-speed USB device number 11 using xhci_hcd
[ 1120.982939] usb 1-14: New USB device found, idVendor=0525, idProduct=a4a2, bcdDevice= 5.15
[ 1120.982951] usb 1-14: New USB device strings: Mfr=1, Product=2, SerialNumber=0
[ 1120.982956] usb 1-14: Product: RNDIS/Ethernet Gadget
[ 1120.982960] usb 1-14: Manufacturer: Linux 5.15.0-rc2-postmarketos-exynos4 with 12480000.hsotg
[ 1120.983969] cdc_subset: probe of 1-14:1.0 failed with error -22
[ 1120.985850] cdc_ether 1-14:1.0 usb0: register 'cdc_ether' at usb-0000:00:14.0-14, CDC Ethernet Device, 6e:a1:9d:91:14:fa
[ 1120.995419] cdc_ether 1-14:1.0 enp0s20f0u14: renamed from usb0

while normally, when I can ssh, it shows something like:

[  502.941283] usb 1-2: USB disconnect, device number 6
[  516.040837] usb 1-14: new high-speed USB device number 7 using xhci_hcd
[  516.186559] usb 1-14: New USB device found, idVendor=04e8, idProduct=685d, bcdDevice= 2.1b
[  516.186572] usb 1-14: New USB device strings: Mfr=1, Product=2, SerialNumber=0
[  516.186577] usb 1-14: Product: Gadget Serial
[  516.186581] usb 1-14: Manufacturer: SAMSUNG
[  516.208283] usbcore: registered new interface driver cdc_acm
[  516.208285] cdc_acm: USB Abstract Control Model driver for USB modems and ISDN adapters

@Newbyte please try it on your device!

Closes https://gitlab.com/postmarketOS/pmaports/-/issues/1214