build, qt: Drop redundant -lxcb-static flag

The removed flag has been already linked with Qt5XcbQpa.

build-aux/m4/bitcoin_qt.m4

@@ -151,7 +151,7 @@ AC_DEFUN([BITCOIN_QT_CONFIGURE],[
     elif test "x$TARGET_OS" = xlinux; then
       dnl workaround for https://bugreports.qt.io/browse/QTBUG-74874
       AX_CHECK_LINK_FLAG([-lxcb-shm], [QT_LIBS="-lxcb-shm $QT_LIBS"], [AC_MSG_ERROR([could not link against -lxcb-shm])])
-      _BITCOIN_QT_CHECK_STATIC_PLUGIN([QXcbIntegrationPlugin], [-lqxcb -lxcb-static])
+      _BITCOIN_QT_CHECK_STATIC_PLUGIN([QXcbIntegrationPlugin], [-lqxcb])
       AC_DEFINE(QT_QPA_PLATFORM_XCB, 1, [Define this symbol if the qt platform is xcb])
     elif test "x$TARGET_OS" = xdarwin; then
       AX_CHECK_LINK_FLAG([[-framework Carbon]],[QT_LIBS="$QT_LIBS -framework Carbon"],[AC_MSG_ERROR(could not link against Carbon framework)])