tests/tcg: fix unused variable in linux-test

The latest hexagon compiler picks up that we never consume wcount.
Given the name of the #define that rcount checks against is WCOUNT_MAX
I figured the check just got missed.
Signed-off-by: NAlex Bennée <alex.bennee@linaro.org>
Reviewed-by: NPhilippe Mathieu-Daudé <philmd@linaro.org>
Message-Id: <20221221090411.1995037-5-alex.bennee@linaro.org>
(cherry picked from commit 2bc6c794)
Signed-off-by: NMichael Tokarev <mjt@tls.msk.ru>

tests/tcg/multiarch/linux/linux-test.c

@@ -354,13 +354,17 @@ static void test_pipe(void)
             if (FD_ISSET(fds[0], &rfds)) {
                 chk_error(read(fds[0], &ch, 1));
                 rcount++;
-                if (rcount >= WCOUNT_MAX)
+                if (rcount >= WCOUNT_MAX) {
                     break;
+                }
             }
             if (FD_ISSET(fds[1], &wfds)) {
                 ch = 'a';
                 chk_error(write(fds[1], &ch, 1));
                 wcount++;
+                if (wcount >= WCOUNT_MAX) {
+                    break;
+                }
             }
         }
     }