ARM: 6659/1: Thumb-2: Make CONFIG_OABI_COMPAT depend on !CONFIG_THUMB2_KERNEL

rmk says: "You might as well make OABI_COMPAT depend on !THUMB2_KERNEL.
OABI userland is useless without FPA support."

nwfpe doesn't work with Thumb-2 anyway and will probably never get
ported, so I can't argue with that.

This patch implements the dependency change.

Signed-off-by: Dave Martin <dave.martin@linaro.org>
Acked-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>