FogBugz #191875: Enable U-Boot command line editing

Enhance U-Boot command console experience by enabling
command line editing. User can use up arrow to retrieve
previous typed command and edit it later on.

Signed-off-by: Chin Liang See <clsee@altera.com>
FogBugz #191882: Move away handoff path from common config

Move away handoff file include paths from socfpga_common.h
to device specific configuration file (such as socfpga_cyclone5.h).
This will ensure other board configuration file can include
socfpga_common.h. This is to avoid code duplication among boards
who are using SOCFPGA device.

Signed-off-by: Chin Liang See <clsee@altera.com>