Added BFD_RELOC_32 relocation.

[Molorius]

This adds the BFD_RELOC_32 relocation to esp32 and esp32s2. Tested with both.

This allows you to use the address of a label as a number, such as:

    .data
important:
    .long 0

important_addr:
    .long important

Tested with both the label and the number in different sections, different .S files, etc. I can provide a test project if needed.