riscv: hwcap: Don't alphabetize ISA extension IDs

riscv: hwcap: Don't alphabetize ISA extension IDs

While the comment above the ISA extension ID definitions says
"Entries are sorted alphabetically.", this stopped being good
advice with commit d8a3d8a75206 ("riscv: hwcap: make ISA extension
ids can be used in asm"), as we now use macros instead of enums.
Reshuffling defines is error-prone, so, since they don't need to be
in any particular order, change the advice to just adding new
extensions at the bottom. Also, take the opportunity to change
spaces to tabs, merge three comments into one, and move the base
and max defines into more logical locations wrt the ID definitions.

Signed-off-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20230209123636.123537-1-ajones@ventanamicro.com
Cc: stable@vger.kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>