package/lvm2: drop optional readline dependency

lvm2 is licensed under GPL-2.0, which is not license compatible with
readline (GPL-3.0+), so drop the optional dependency and add a comment
explaining why.

Notice: The readline support is only used when the raw lvm tool is called
without arguments.

Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>
(cherry picked from commit be72d8c9e620d64a177c17a1611ecd9b3dfbdbcd)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/lvm2/lvm2.mk

@@ -28,13 +28,8 @@ LVM2_DEPENDENCIES += host-pkgconf libaio
 # take into account the toolchain passed at configure time.
 LVM2_MAKE_ENV = $(TARGET_CONFIGURE_OPTS)
 
-ifeq ($(BR2_PACKAGE_READLINE),y)
-LVM2_DEPENDENCIES += readline
-else
-# v2.02.44: disable readline usage, or binaries are linked against provider
-# of "tgetent" (=> ncurses) even if it's not used..
+# package/readline is GPL-3.0+, so not license compatible
 LVM2_CONF_OPTS += --disable-readline
-endif
 
 ifeq ($(BR2_PACKAGE_LIBSELINUX),y)
 LVM2_CONF_OPTS += --enable-selinux