board/BuR/common: prepare for compiling common into non AM33XX boards

Today the BuR common stuff is only used on AM33XX boards. In future we
plan to have many other platforms than AM33XX so we have to move arch-
specific #include(s) to responsible #ifdef sections. By the way we drop
unneeded #include(s).

Signed-off-by: Hannes Schmelzer <hannes.schmelzer@br-automation.com>
1 file changed