clover: use correct typenames for compat::pair's first/second

Seems to be a typo judging from the overall declaration of the
template.

Cc: EdB <edb+mesa@sigluy.net>
Cc: Francisco Jerez <currojerez@riseup.net>
Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com>
Reviewed-by: Francisco Jerez <currojerez@riseup.net>

src/gallium/state_trackers/clover/util/compat.hpp

@@ -417,8 +417,8 @@ namespace clover {
          pair(T first, S second) :
             first(first), second(second) {}
 
-         S first;
-         T second;
+         T first;
+         S second;
       };
 
       class exception {