doc only: Correct fan presence recipe comment

(From meta-phosphor rev: a84cf3be7d0ca03fa69f57a954df25c5b8a8cdb4)

Change-Id: Id2bb07dba886a221821ca1f15f6d3169e5926fb2
Signed-off-by: Matthew Barth <msbarth@us.ibm.com>
Signed-off-by: Brad Bishop <bradleyb@fuzziesquirrel.com>
diff --git a/meta-phosphor/recipes-phosphor/fans/phosphor-fan-presence-config.bb b/meta-phosphor/recipes-phosphor/fans/phosphor-fan-presence-config.bb
index 30da6ea..d4176c5 100644
--- a/meta-phosphor/recipes-phosphor/fans/phosphor-fan-presence-config.bb
+++ b/meta-phosphor/recipes-phosphor/fans/phosphor-fan-presence-config.bb
@@ -1,7 +1,7 @@
 # Provides the config file for the phosphor-fan-presence application.
 # The default config file is empty.  To provide a real one,
 # append this recipe in a layer, add:
-# FILESEXTRAPATHS_prepend := "${THISDIR}/${PN}:"
+# FILESEXTRAPATHS_prepend := "${THISDIR}/${BPN}:"
 # and provide a config file.
 
 SUMMARY = "Config file for phosphor-fan-presence"