configure.ac: remove dependency on mtdev

It's been unused since the legacy (non-libinput) input backends have
been removed.

Signed-off-by: Arnaud Vrac <rawoul@gmail.com>
Reviewed-by: Quentin Glidic <sardemff7+git@sardemff7.net>
diff --git a/configure.ac b/configure.ac
index 1aca3d4..0ea7b70 100644
--- a/configure.ac
+++ b/configure.ac
@@ -199,7 +199,7 @@
 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 >= 1.1.0])
+  PKG_CHECK_MODULES(DRM_COMPOSITOR, [libudev >= 136 libdrm >= 2.4.30 gbm])
   PKG_CHECK_MODULES(DRM_COMPOSITOR_GBM, [gbm >= 10.2],
 		    [AC_DEFINE([HAVE_GBM_FD_IMPORT], 1, [gbm supports dmabuf import])],
 		    [AC_MSG_WARN([gbm does not support dmabuf import, will omit that capability])])
@@ -242,7 +242,7 @@
                [test x$enable_fbdev_compositor = xyes])
 AS_IF([test x$enable_fbdev_compositor = xyes], [
   AC_DEFINE([BUILD_FBDEV_COMPOSITOR], [1], [Build the fbdev compositor])
-  PKG_CHECK_MODULES([FBDEV_COMPOSITOR], [libudev >= 136 mtdev >= 1.1.0])
+  PKG_CHECK_MODULES([FBDEV_COMPOSITOR], [libudev >= 136])
 ])
 
 AC_ARG_ENABLE([rdp-compositor], [  --enable-rdp-compositor],,