Update IMPL_*_SIGALG to not have to stringify parameter

Update IMPL_*_SIGALG to not have to stringify parameter

Noted while playing with some c-style tools that these macros got
mis-handled when doing style changes.  Specifically, the last parameter,
as it passed externally as a token, but stringified internal to the
associated macro, got handled as an arithmetic expression rather than a
string.

Given that the only thing this parameter is used for is as a string, cut
out the middle man and just pass it as a string in the first place

Reviewed-by: Saša Nedvědický <sashan@openssl.org>
Reviewed-by: Richard Levitte <levitte@openssl.org>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
Reviewed-by: Matt Caswell <matt@openssl.org>
Reviewed-by: Paul Dale <ppzgs1@gmail.com>
Reviewed-by: Todd Short <todd.short@me.com>
(Merged from https://github.com/openssl/openssl/pull/27579)