gcc: drop TARGET_SYS workaround

This is no longer needed, as the external toolchain no longer sets
TARGET_PREFIX.

Signed-off-by: Christopher Larson <chris_larson@mentor.com>

core/recipes-devtools/gcc/gcc_%.bbappend

@@ -1,6 +1,3 @@
-# Align TARGET_SYS and TARGET_PREFIX to avoid binary links which include both
-TARGET_SYS := "${@TARGET_PREFIX[:-1]}"
-
 # FIXME: resolve gcc version mismatch issues with ${libdir}/gcc/*/<version>
 # filesystem paths
 python () {