radv: Break up radv_shader_nir_to_asm

radv: Break up radv_shader_nir_to_asm

radv_shader_nir_to_asm actually had 3 functions: compiling the NIR to
asm, uploading the shaders and generating debug info for them.
This reduces the functionality of radv_shader_nir_to_asm to only compile
NIR to asm. Uploading the shader and generating debug info is split into
separate functions.

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/23516>