nouveau: avoid LTO ODR warning (v2)

nouveau: avoid LTO ODR warning (v2)

../src/gallium/drivers/nouveau/codegen/nv50_ir_target_nv50.cpp:69:8: warning: type ‘struct opProperties’ violates the C++ One Definition Rule [-Wodr]
   69 | struct opProperties
      |        ^
../src/gallium/drivers/nouveau/codegen/nv50_ir_target_nvc0.cpp:88:8: note: a different type is defined in another translation unit
   88 | struct opProperties
      |        ^
../src/gallium/drivers/nouveau/codegen/nv50_ir_target_nv50.cpp:77:17: note: the first difference of corresponding definitions is field ‘fShared’
   77 |    unsigned int fShared : 3;
      |                 ^
../src/gallium/drivers/nouveau/codegen/nv50_ir_target_nvc0.cpp:96:17: note: a field with different name is defined in another translation unit
   96 |    unsigned int fImmd  : 4; // last bit indicates if full immediate is suppoted

nvc0 code also has the same thing.

v2: rename both paths (Karol)

Reviewed-by: Karol Herbst <kherbst@redhat.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/5873>