crypto: x86/sha256 - Add parentheses around macros' single arguments

The macros FOUR_ROUNDS_AND_SCHED and DO_4ROUNDS rely on an
unexpected/undocumented behavior of the GNU assembler, which might
change in the future
(https://sourceware.org/bugzilla/show_bug.cgi?id=32073).

    M (1) (2) // 1 arg !? Future: 2 args
    M 1 + 2   // 1 arg !? Future: 3 args

    M 1 2     // 2 args

Add parentheses around the single arguments to support future GNU
assembler and LLVM integrated assembler (when the IsOperator hack from
the following link is dropped).

Link: https://github.com/llvm/llvm-project/commit/055006475e22014b28a070db1bff41ca15f322f0


Signed-off-by: Fangrui Song <maskray@google.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>