x86/crc32: update prototype for crc32_pclmul_le_16()

x86/crc32: update prototype for crc32_pclmul_le_16()

- Change the len parameter from unsigned int to size_t, so that the
  library function which takes a size_t can safely use this code.

- Move the crc parameter to the front, as this is the usual convention.

Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20241202010844.144356-13-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>