recipes: pre/post actions

A number of the recipes did not properly label their pre and post
actions, causing the actions to occur in all split packages.  This
was corrected by defaulting to _${PN} in most cases.

Signed-off-by: Mark Hatle <mark.hatle@windriver.com>

meta/recipes-kernel/update-modules/update-modules_1.0.bb

@@ -10,7 +10,7 @@ PR = "r8"
 SRC_URI = "file://update-modules \
            file://COPYING.GPL"
 
-pkg_postinst() {
+pkg_postinst_${PN} () {
 if [ "x$D" != "x" ]; then
 	exit 1
 fi