v3d: fix tfu_supports_tex_format() param type, and document why

tex_format should be enum V3DX(Texture_Data_Formats), but using that enum type in the header requires including v3dx_pack.h, which triggers circular include dependencies issues, so use a uint32_t for now.

"fix" the one place that was using the correct enum, because doing so triggers -Wenum-int-mismatch in GCC 13 as the function declaration doesn't match the function definition.

Reported-by: @daenzer in !22718 (33d94e0e)