Revision codes for Pi4 rev1.5 are missing

In the table from [New-style Revision Codes in Use](https://www.raspberrypi.com/documentation/computers/raspberry-pi.html#new-style-revision-codes-in-use), the revision codes for the seen-in-the-wild Pi4B rev1.5 is absent.

Pi4B 2GB rev1.5:
```
Hardware        : BCM2711
Revision        : b03115
Serial          : <16 hex chars>
Model           : Raspberry Pi 4 Model B Rev 1.5
```
