scripts/gdb: If not building expat for gdb, disable

--with-expat=yes is unconditionally passed to the gdb configure
stage, instead of respecting the ${do_expat} decision.

Disable if not needed. Prevents error building canadian cross;

configure: error: expat is missing or unusable

Where configure stage fails to find expat on the host compiler.

Signed-off-by: "David Holsgrove" <david.holsgrove@xilinx.com>
Signed-off-by: Bryan Hundven <bryanhundven@gmail.com>
Message-Id: <4c4410a2a8aab24a29c5.1349244128@localhost.localdomain>
PatchWork-Id: 188711

# This file declares functions for bare metal kernel (IE. none)

# Copyright 2008 Yann E. MORIN

# Licensed under the GPL v2. See COPYING in the root of this package

CT_DoKernelTupleValues() {

    # For bare-metal, there is no kernel part in the tuple

    CT_TARGET_KERNEL=

}

do_kernel_get() {

    :

}

do_kernel_extract() {

    :

}

do_kernel_headers() {

    :

}