A recent binutils patch added the LDGOLD variable but its already used
for controlling EXTRA_OECONF options for gold. Separate the two variables
to different names to avoid build warnings and confusion.
(From OE-Core rev: 713c83fd00ab16250f05b0c3933f0c8178b8a33e)
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>