beaglebone: bare metal c example source modified, exception vector table removed

Signed-off-by: Samuel Casa <samuelcasa9@gmail.com>
beaglebone: bare metal c example, makefile modified

Signed-off-by: Samuel Casa <samuelcasa9@gmail.com>
beaglebone: bare metal c example, readme modified

Signed-off-by: Samuel Casa <samuelcasa9@gmail.com>