tridentfb: add imageblit acceleration for Blade3D family

Add imageblit acceleration for the Blade3D family of cores.  The code is
based on code from the cyblafb driver.

It is a step toward assimilating back the cyblafb driver into the
tridentfb driver.  The cyblafb driver handles a subfamily of the Trident
Blade3d cores.

Signed-off-by: Krzysztof Helt <krzysztof.h1@wp.pl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>