[openssl/openssl] a5b0c5: s390x: Fix build on s390x with 'disable-asm'

[Ingo Franzki]

  Branch: refs/heads/master
  Home:   https://github.com/openssl/openssl
  Commit: a5b0c568dbefddd154f99011d7ce76cfbfadb67a
      https://github.com/openssl/openssl/commit/a5b0c568dbefddd154f99011d7ce76cfbfadb67a
  Author: Ingo Franzki <ifranzki at linux.ibm.com>
  Date:   2024-02-06 (Tue, 06 Feb 2024)

  Changed paths:
    M include/crypto/bn.h

  Log Message:
  -----------
  s390x: Fix build on s390x with 'disable-asm'

Do not define S390X_MOD_EXP for a NO_ASM build, this would result in
unresolved externals for s390x_mod_exp and s390x_crt.

Signed-off-by: Ingo Franzki <ifranzki at linux.ibm.com>

Reviewed-by: Hugo Landau <hlandau at openssl.org>
Reviewed-by: Tomas Mraz <tomas at openssl.org>
(Merged from https://github.com/openssl/openssl/pull/23458)