Clean up custom LoadTextureBlock in z_map_mark.c and z_lmap_mark.c

[mzxrules]

the definitions of gdpLoadTextureBlock and similar use token replacement to construct the constants passed into macro's internal display list calls, meaning the macro cannot be used to pass in raw IM_SIZ values during runtime. To solve this, the original uses a series of six lookup tables to fetch the correct constant values.

To get the original gdpLoadTextureBlock to reference these arrays, decomp currently creates 6 specially named defines for every uniquely named siz argument that needs to be passed into gdpLoadTextureBlock.

There's a few things I find wrong with this:

• In general, I find it poor design to have to create 6 defines for every different possible argument you'd pass into a macro, and I fear that somebody who is too afraid to look into the gdpLoadTextureBlock internals is going to blindly copypaste the pattern because it just works
• If a custom mod updates gdpLoadTextureBlock to allow raw IM_SIZ values, the changes won't automatically eliminate the array access since the decomp code still passes in the result of the sBaseImageSizes lookup into the macro.
• Technically, z_map_mark.c and z_lmap_mark.c is coupled to gdpLoadTextureBlock's internals more than it probably should be.