[BUG] RPi 4B SPI driver doesn't work with alternates

### Description / Steps to reproduce the issue

The current SPI driver doesn't work with the listed alternates in the BCM2711 peripheral datasheet. Only SPI0 currently works, as SPI3-6 needs magic registers to be configured before they can work.

In the Linux supported version, this is done by the Linux driver. Even with the correct dt-overlay file from the Raspberry Pi foundation's repository, the alternate interfaces are not enabled. The source code of other implementation may need to be examined to locate these registers.

### On which OS does this issue occur?

[OS: Linux]

### What is the version of your OS?

Arch Linux 6.6

### NuttX Version

master

### Issue Architecture

[Arch: arm64]

### Issue Area

[Area: Drivers]

### Host information

_No response_

### Verification

- [x] I have verified before submitting the report.