drivers/rpmsg: remove depends on CONFIG_EXPERIMENTAL

The CONFIG_EXPERIMENTAL config item has not carried much meaning for a
while now and is almost always enabled by default. As agreed during the
Linux kernel summit, remove it from any "depends on" lines in Kconfigs.

CC: Ohad Ben-Cohen <[e-mail]>
CC: Rusty Russell <[e-mail]>
Signed-off-by: Kees Cook <[e-mail]>
Acked-by: Rusty Russell <[e-mail]>

drivers/rpmsg/Kconfig

···
-menu "Rpmsg drivers (EXPERIMENTAL)"
+menu "Rpmsg drivers"
 
 # RPMSG always gets selected by whoever wants it
 config RPMSG
 	tristate
 	select VIRTIO
-	depends on EXPERIMENTAL
 
 endmenu