Add definitions of SYSCFG registers and memory remap function
In debug_uart.c, only include softirq.h with CONFIG_KDB
Correct the type(uint32_t --> size_t) of "size" in function queue_init.
Loader merged with f9 kernel(containing user space)

It is WIP version of loader.  The following are future work.
   1. Merged build system with f9 kernel.
   2. Remove duplicated files in loader(xxx_ld.c).  They are just
      for easy building.