[ARM] 3909/1: Disable UWIND_INFO for ARM (again)

According to Daniel Jacobowitz, UNWIND_INFO is not useful on ARM, and
in fact doesn't even compile.

This patch disables the option for ARM.

Signed-off-by: Kevin Hilman <khilman@mvista.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>