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

--- gcc-4.3.2.orig/gcc/config/arm/linux-eabi.h	2009-09-08 23:46:44.000000000 +0200

+++ gcc-4.3.2/gcc/config/arm/linux-eabi.h	2009-09-08 23:46:51.000000000 +0200

@@ -44,7 +44,7 @@

    The ARM10TDMI core is the default for armv5t, so set

    SUBTARGET_CPU_DEFAULT to achieve this.  */

 #undef  SUBTARGET_CPU_DEFAULT

-#define SUBTARGET_CPU_DEFAULT TARGET_CPU_arm10tdmi

+#define SUBTARGET_CPU_DEFAULT TARGET_CPU_arm9tdmi

 /* TARGET_BIG_ENDIAN_DEFAULT is set in

    config.gcc for big endian configurations.  */