- Rename the lcall system call handler from Xsyscall to Xlcall_syscall

- Rename the lcall system call handler from Xsyscall to Xlcall_syscall
  to be more like Xint0x80_syscall and less like c function syscall().
- Reduce code duplication between the int0x80 and lcall handlers by
  shuffling the elfags into the right place, saving the sizeof the
  instruction in tf_err and jumping into the common int0x80 code.

Reviewed by:	peter