target/i386: clean up cpu_cc_compute_all

target/i386: clean up cpu_cc_compute_all

cpu_cc_compute_all() has an argument that is always equal to CC_OP for historical
reasons (dating back to commit a7812ae4123, "TCG variable type checking.", 2008-11-17,
which added the argument to helper_cc_compute_all).  It does not make sense for the
argument to have any other value, so remove it and clean up some lines that are not
too long anymore.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>