riscv: cpufeature: add zve32[xf] and zve64[xfd] isa detection

riscv: cpufeature: add zve32[xf] and zve64[xfd] isa detection

Multiple Vector subextensions are added. Also, the patch takes care of
the dependencies of Vector subextensions by macro expansions. So, if
some "embedded" platform only reports "zve64f" on the ISA string, the
parser is able to expand it to zve32x zve32f zve64x and zve64f.

Signed-off-by: Andy Chiu <andy.chiu@sifive.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20240510-zve-detection-v5-5-0711bdd26c12@sifive.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>