Use find_cfgs() helper from cml1.bbclass

Since Yocto commit 329665d cml1.bbclass now contains the function
find_cfgs(). This bbclass is already inherited.

Signed-off-by: Alexander Vickberg <wickbergster@gmail.com>
Reviewed-by: Stefano Babic <sbabic@denx.de>

recipes-support/swupdate/swupdate.inc

@@ -75,10 +75,6 @@ EXTRA_OEMAKE += " O=${B} HOSTCC="${BUILD_CC}" HOSTCXX="${BUILD_CXX}" LD="${CC}"
 
 DEPENDS += "kern-tools-native"
 
-# returns all the elements from the src uri that are .cfg files
-def find_cfgs(d):
-    return [s for s in src_patches(d, True) if s.endswith('.cfg')]
-
 python () {
     import re