Cleanup on Serial initialization for BeagleBoard and Devkit8000

*) Define beagle_serial_init(void) to its own function
*) Separate Serial Initialization to different files
*) Modify Makefile to reflect the change

Signed-off-by: Muhammad Sumyandityo Noor <lynxluna@gmail.com>
Deleted DEVKIT8000 Blankon Config (cleanup)

Signed-off-By: Muhammad Sumyandityo Noor (lynxluna@gmail.com)
Merge branch 'master' of github.com:lynxluna/linux