Remove filename argument to x86 asm_init.

The assembler already knows the actual path to the generated file and,
in other perlasm architectures, is left to manage debug symbols itself.
Notably, in OpenSSL 1.1.x's new build system, which allows a separate
build directory, converting .pl to .s as the scripts currently do result
in the wrong paths.

This also avoids inconsistencies from some of the files using $0 and
some passing in the filename.

Reviewed-by: Richard Levitte <levitte@openssl.org>
Reviewed-by: Andy Polyakov <appro@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/3431)
