wined3d: Add NVIDIA Geforce GT 750M to supported device list.

[Jonas Maebe]

FWIW, I have such an NVIDIA Geforce GT 750M card (under OS X 10.9.5) and
Crossover 13.2 returned 768MB of vram for it. Crossover 14/14.0.1
returns 128MB instead, which resulted in a number of games suddenly
crashing because they ran out of VRAM. This issue was quickly diagnosed
by the helpful Codeweavers support person, and resolved by adding the
registry entry to override the video memory size.

Looking at the current source code, I assume that's because
shader_arb_get_caps() can set the shader_caps->vs_version maximally to
3, while d3d_level_from_caps() will only return WINED3D_D3D_LEVEL_10 for
shader_caps->vs_version==4. As a result, d3d_level_from_caps now returns
WINED3D_D3D_LEVEL_9_SM3, which is translated for an unknown NVidia card
into CARD_NVIDIA_GEFORCE_6800. That one is indeed defined as having
128MB of VRAM.