[gentoo-embedded] default fp selection with armv6/armv7 targets

[Mike Frysinger]

currently, we have the system:
	- if chost matches *-softfloat-*, you get softfloat
	- if chost matches *-hardfloat-*, you get hardfloat
	- for everything else, you get the gcc default

with the standardization work going on with armv7+ and hardfp, i've made the 
following change:
	- if chost matches armv7*-softfloat-*, you got softfloat
	- for all other armv7* targets, you get hardfloat vfp3-d16

along those lines, i've also slipped in:
	- if chost matches armv6*-softfloat-*, you got softfloat
	- for all other armv6* targets, you get hardfloat vfp

considering vfp is required baseline in these cores now, it doesn't make sense 
to not use it if the user has explicitly stated they're targeting these 
arches.

if you really want to use a different default, you can still use EXTRA_ECONF to 
set whatever you want.
-mike