mali-t76x: add new package

Package provides the binary user-space components for the ARM Mali
Midgard T76X GPU.

Note that this package requires a kernel with the ARM Mali Midgard GPU
Kernel Drivers enabled.

Signed-off-by: Ariel D'Alessandro <ariel@vanguardiasur.com.ar>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>