usbmount: depend on udev rather than selecting it

udev is much more than a library, so we shouldn't use select to silently
enable it.

Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>

package/usbmount/Config.in

@@ -2,7 +2,7 @@ config BR2_PACKAGE_USBMOUNT
 	bool "usbmount"
 	depends on BR2_LARGEFILE # util-linux
 	depends on BR2_USE_WCHAR # util-linux
-	select BR2_PACKAGE_UDEV
+	depends on BR2_PACKAGE_UDEV
 	select BR2_PACKAGE_LOCKFILE_PROGS
 	select BR2_PACKAGE_UTIL_LINUX
 	select BR2_PACKAGE_UTIL_LINUX_LIBBLKID
@@ -13,4 +13,4 @@ config BR2_PACKAGE_USBMOUNT
 	  http://usbmount.alioth.debian.org/
 
 comment "usbmount requires a toolchain with LARGEFILE + WCHAR support"
-	depends on !(BR2_LARGEFILE && BR2_USE_WCHAR)
+	depends on !(BR2_LARGEFILE && BR2_USE_WCHAR) && BR2_PACKAGE_UDEV