Update buildroot from 17.02.2 -> 17.02.3

bsp/buildroot/toolchain/helpers.mk

@@ -132,22 +132,12 @@ check_kernel_headers_version = \
 # $1: path to gcc
 # $2: expected gcc version
 #
-# Some details about the sed expression:
-# - 1!d
-#   - delete if not line 1
-#
-# - s/^[^)]+\) ([^[:space:]]+).*/\1/
-#   - eat all until the first ')' character followed by a space
-#   - match as many non-space chars as possible
-#   - eat all the remaining chars on the line
-#   - replace by the matched expression
-#
 check_gcc_version = \
 	expected_version="$(strip $2)" ; \
 	if [ -z "$${expected_version}" ]; then \
 		exit 0 ; \
 	fi; \
-	real_version=`$(1) --version | sed -r -e '1!d; s/^[^)]+\) ([^[:space:]]+).*/\1/;'` ; \
+	real_version=`$(1) -dumpversion` ; \
 	if [[ ! "$${real_version}" =~ ^$${expected_version}\. ]] ; then \
 		printf "Incorrect selection of gcc version: expected %s.x, got %s\n" \
 			"$${expected_version}" "$${real_version}" ; \