crash: add cross package

This patch adds the cross package for the crash recipe. I've built and
tested crash-cross for ARM on x86_64 host only.

The way to pass GDB_CONF_FLAGS and --target to GDB build without
removing -m32 from CFLAGS is awkward but that is what I could come up
with, without changing the patch files included with the recipe or
breaking target and native builds. Anyone got any ideas on how to
better do this?

Thanks,

     Goran

Signed-off-by: Goran Cengic <cengic@gmail.com>
Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>
Signed-off-by: Armin Kuster <akuster808@gmail.com>