nativesdk: Switch to using nativesdk as a prefix, not a suffix

nativesdk: Switch to using nativesdk as a prefix, not a suffix

As discussed on the mailing lists, using a suffix to package names is
hard and has lead to many recipes having to do PKGSUFFIX games. Its
looking extremely hard to scale nativesdk much further without hacking
many recipes.

By comparison, using a prefix like multilib does works much better and
doesn't involve "hacking" as many recipes. This change converts nativesdk
to use a prefix using the existing multilib infrastructure.

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>