x86: Fix mkcapflags.sh bash-ism

Chocked while compiling linux with dash shell instead of bash
shell. See:

   http://pubs.opengroup.org/onlinepubs/9699919799/utilities/test.htmlSigned-off-by: NSylvain BERTRAND <sylvain.bertrand@gmail.com>
Link: http://lkml.kernel.org/r/20141223123912.GA1386@localhost.localdomainSigned-off-by: NIngo Molnar <mingo@kernel.org>

arch/x86/kernel/cpu/mkcapflags.sh

@@ -28,7 +28,7 @@ function dump_array()
 		# If the /* comment */ starts with a quote string, grab that.
 		VALUE="$(echo "$i" | sed -n 's@.*/\* *\("[^"]*"\).*\*/@\1@p')"
 		[ -z "$VALUE" ] && VALUE="\"$NAME\""
-		[ "$VALUE" == '""' ] && continue
+		[ "$VALUE" = '""' ] && continue
 
 		# Name is uppercase, VALUE is all lowercase
 		VALUE="$(echo "$VALUE" | tr A-Z a-z)"