configure.ac: adjust the dvdread requirement

The same what meson does, and what distributions like openSUSE Leap
(used to) ship.

Fixes commit 4b2c2a7bd0

Signed-off-by: Olaf Hering <olaf@aepfle.de>

configure.ac

@@ -2177,7 +2177,7 @@ AS_IF([test "$SYS" = "linux" -a "${enable_linsys}" != "no"], [
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 dnl dvdread module: check for libdvdread
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-PKG_ENABLE_MODULES_VLC([DVDREAD], [], [dvdread > 6.0.0], [dvdread input module], [auto])
+PKG_ENABLE_MODULES_VLC([DVDREAD], [], [dvdread >= 6.0.0], [dvdread input module], [auto])
 
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 dnl libdvdnav plugin