configure.ac: s/xcb-fixes/xcb-xfixes/

Former is not a thing, even if I have a hacked xcb-fixes.pc on my system.
Thanks for spotting it Mark!

Fixes: 9a90d6a9d4e ("configure.ac: add xcb-fixes to the XCB DRI3 list")
Signed-off-by: Emil Velikov <emil.velikov@collabora.com>
diff --git a/configure.ac b/configure.ac
index b788137..06883a9 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1723,7 +1723,7 @@
 if test x"$enable_dri3" = xyes; then
     DEFINES="$DEFINES -DHAVE_DRI3"
 
-    dri3_modules="x11-xcb xcb >= $XCB_REQUIRED xcb-dri3 xcb-fixes xcb-present xcb-sync xshmfence >= $XSHMFENCE_REQUIRED"
+    dri3_modules="x11-xcb xcb >= $XCB_REQUIRED xcb-dri3 xcb-xfixes xcb-present xcb-sync xshmfence >= $XSHMFENCE_REQUIRED"
     PKG_CHECK_MODULES([XCB_DRI3], [$dri3_modules])
 fi