fp5280g2: Fix the file extra path error

When built the related SDK on fp5280g2, since the wrong FILESEXTRAPATHS
were defined and the build failed.

Tested: built successfully on fp5280g2 using related SDK.

Signed-off-by: George Liu <liuxiwei@inspur.com>
Change-Id: I57cc72ec2eb1d977bd91933573dc4aa4b30cb1e0
diff --git a/meta-fp5280g2/recipes-phosphor/fans/phosphor-fan_%.bbappend b/meta-fp5280g2/recipes-phosphor/fans/phosphor-fan_%.bbappend
index 1db0942..2e3dcad 100644
--- a/meta-fp5280g2/recipes-phosphor/fans/phosphor-fan_%.bbappend
+++ b/meta-fp5280g2/recipes-phosphor/fans/phosphor-fan_%.bbappend
@@ -1,4 +1,4 @@
-FILESEXTRAPATHS_prepend_fp5280g2:= "${THISDIR}/${BPN}:"
+FILESEXTRAPATHS_prepend := "${THISDIR}/${BPN}:"
 
 # Package configuration
 FAN_PACKAGES += " \