[PING][PATCH v2] MIPS: Add conditions for use of the -mmips16e2 and -mips16 option.

Ping for https://gcc.gnu.org/pipermail/gcc-patches/2025-January/673877.html Thanks, Jie

[PATCH v2] MIPS: Add conditions for use of the -mmips16e2 and -mips16 option.

Changes from V1: * Raise the minimal revision to r2. MIPS16e2 ASE is a superset of MIPS16e ASE, which is again a superset of MIPS16 ASE. Later, all of them are forbidden in Release 6. Make -mmips16e2 imply -mips16 as the ASE requires, so users won't be surprised even if they expect it to. Meanwhi