riscv: Sort the ISA extension array alphabetically

Let us follow alphabetical order for listing ISA extensions in
the isa_info_arr[] array.

Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Link: https://lore.kernel.org/r/20230712163501.1769737-6-apatel@ventanamicro.com


Signed-off-by: Will Deacon <will@kernel.org>