binutils/binutils: fix extra config array variable name

The changeset 2467 #200836977ce6 missed renaming one occurrence of
CT_BINUTILS_EXTRA_CONFIG to CT_BINUTILS_EXTRA_CONFIG_ARRAY, which is fixed by
this patch.

Signed-off-by: "Benoît Thébaudeau" <benoit.thebaudeau@advansee.com>
(transplanted from 8946dd980d9e6c3da3b8f63fe7e35f4af94acf2f)

 # Default test suite configuration

 # Default DejaGnu configuration

 DG_TOOLNAME = gcc

 DG_TARGET_HOSTNAME = 127.0.0.1

 DG_TARGET_USERNAME = root

 # Default tests

 DG_C_TESTS = 

 DG_CPP_TESTS =