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: NJohn Clements <john.clements@amd.com>
Signed-off-by: NCandice Li <candice.li@amd.com>
Reviewed-by: NTao Zhou <tao.zhou1@amd.com>
Reviewed-by: NHawking Zhang <Hawking.Zhang@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>