[lldb][AArch64][Linux] Add field information for the fpsr register (#71651)

This one is easy because none of the fields depend on extensions. Only
thing to note is that I've ignored some AArch32 only fields.

```
(lldb) register read fpsr
    fpsr = 0x00000000
         = (QC = 0, IDC = 0, IXC = 0, UFC = 0, OFC = 0, DZC = 0, IOC = 0)
```