fix compilation issues in aarch64 ports

* fix: corrected syntax of sys with encoding space.
* fix: corrected syntax of inline asm constrain list.
* fix: corrected the #include name error
* fix: corrected the use of asm directive to load symbol to reg
* fix: replace the invalid ldr into sp by using add to deduce the value
* ref: remove the sp_el1_saved from exec_param as no longer needed
* fix: add couple missing headers
* fix: other general fixes with type conversions