deb-pkg: Add automatic support for armhf architecture

The Debian armhf architecture uses the ARM EABI hard-float variant,
whereas armel uses the soft-float variant.  Although the kernel
doesn't use FP itself, CONFIG_VFP must be enabled to support
hard-float userland and will probably be disabled when supporting a
soft-float userland.  So set the architecture to armhf by default when
CONFIG_AEABI and CONFIG_VFP are both enabled.

Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Acked-by: Ian Campbell <ijc@hellion.org.uk>
Acked-by: Fathi Boudra <fathi.boudra@linaro.org>
Reviewed-by: Riku Voipio <riku.voipio@linaro.org>
Signed-off-by: Michal Marek <mmarek@suse.cz>