Move nv30, nv50 and nvc0 to nouveau.

Move nv30, nv50 and nvc0 to nouveau.

It is planned to ship openSUSE 13.1 with -shared libs.
nouveau.la, nv30.la, nv50.la and nvc0.la are currently LIBADDs in all nouveau
related targets.
This change makes it possible to easily build one shared libnouveau.so which is
then LIBADDed.
Also dlopen will be faster for one library instead of three and build time on
-jX will be reduced.

Whitespace fixes were requested by 'git am'.

Signed-off-by: Johannes Obermayr <johannesobermayr@gmx.de>
Acked-by: Christoph Bumiller <christoph.bumiller@speed.at>
Acked-by: Ian Romanick <ian.d.romanick@intel.com>