drm/amdgpu: Optimize TA load/unload/invoke debugfs interfaces

1. Add a function pointer structure ta_funcs to psp context
2. Make the interfaces generic to all TAs
3. Leverage exisitng TA context and remove unused functions
4. Fix return code bugs

v2: Add comments for ta funcs macros and correct typo

Reviewed-by: Hawking Zhang <Hawking.Zhang@amd.com>
Signed-off-by: Candice Li <candice.li@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drm/amdgpu: Fix build warning for TA debugfs interface

Remove the redundant codes to fix build warning
when CONFIG_DEBUG_FS is disabled.

Reported-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Candice Li <candice.li@amd.com>
Reviewed-by: Yang Wang <kevinyang.wang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drm/amdgpu: Add debugfs TA load/unload/invoke support

v1:
Add debugfs support to load/unload/invoke TA in runtime.

v2:
1. Update some variables to static.
2. Use PAGE_ALIGN to calculate shared buf size directly.
3. Remove fp check.
4. Update debugfs from read to write.

Signed-off-by: John Clements <john.clements@amd.com>
Signed-off-by: Candice Li <candice.li@amd.com>
Reviewed-by: Tao Zhou <tao.zhou1@amd.com>
Reviewed-by: Hawking Zhang <Hawking.Zhang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>