build: Tighten mtdev dependency to reflect requirement

The mtdev_new_open symbol was added in 1.1.0.
diff --git a/configure.ac b/configure.ac
index 26c4283..888152b 100644
--- a/configure.ac
+++ b/configure.ac
@@ -73,7 +73,7 @@
 AM_CONDITIONAL(ENABLE_DRM_COMPOSITOR, test x$enable_drm_compositor = xyes)
 if test x$enable_drm_compositor = xyes; then
   AC_DEFINE([BUILD_DRM_COMPOSITOR], [1], [Build the DRM compositor])
-  PKG_CHECK_MODULES(DRM_COMPOSITOR, [libudev >= 136 libdrm >= 2.4.30 gbm mtdev])
+  PKG_CHECK_MODULES(DRM_COMPOSITOR, [libudev >= 136 libdrm >= 2.4.30 gbm mtdev >= 1.1.0])
 fi