When we have python building tools for the host it will not check HOSTXX
variables but only XX variables, for example LDFLAGS and not
HOSTLDFLAGS.

Cc: Simon Glass <sjg@chromium.org>
Reported-by: Heiko Schocher <hs@denx.de>
Fixes: 1905c8fc ("build: Always build the libfdt python module")
Signed-off-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Tested-by: Simon Glass <sjg@chromium.org>
Tested-by: Heiko Schocher <hs@denx.de>