udev: disable udev-cache on beaglebone

With udev-cache enabled, usb kernel modules were not loaded.

Change-Id: I11e5bec4a5b7aa1be30ecb016911a86ab1431dbb
Reviewed-by: Samuli Piippo <samuli.piippo@digia.com>

recipes/udev/udev/beaglebone/udev-cache.default

+# Default for /etc/init.d/udev
+
+# Comment this out to disable device cache
+#DEVCACHE="/etc/dev.tar"

recipes/udev/udev_182.bbappend

@@ -20,7 +20,7 @@
 ##
 #############################################################################
 
-FILESEXTRAPATHS_prepend := "${THISDIR}:"
+FILESEXTRAPATHS_prepend := "${THISDIR}/${PN}:"
 
 SRC_URI += "file://0001-support-multitouch-screens.patch"