[openssl/openssl] 84a0b1: Resolve assembler complains when including loongar...

[zhoumin2]

  Branch: refs/heads/master
  Home:   https://github.com/openssl/openssl
  Commit: 84a0b1b169197e3afdadcdafc9fea65361ff672f
      https://github.com/openssl/openssl/commit/84a0b1b169197e3afdadcdafc9fea65361ff672f
  Author: Min Zhou <zhoumin at loongson.cn>
  Date:   2023-08-28 (Mon, 28 Aug 2023)

  Changed paths:
    M crypto/loongarch_arch.h

  Log Message:
  -----------
  Resolve assembler complains when including loongarch_arch.h

The assembler will complain when we include loongarch_arch.h in
an assembly file as following:

crypto/loongarch_arch.h: Assembler messages:
crypto/loongarch_arch.h:12: Fatal error: no match insn: extern	unsigned int OPENSSL_loongarch_hwcap_P

So, the sentence of `extern unsigned int OPENSSL_loongarch_hwcap_P`
should be guarded with "#ifndef __ASSEMBLER__".

Fixes #21838.

Signed-off-by: Min Zhou <zhoumin at loongson.cn>

Reviewed-by: Hugo Landau <hlandau at openssl.org>
Reviewed-by: Tomas Mraz <tomas at openssl.org>
(Merged from https://github.com/openssl/openssl/pull/21839)