ARM: sirf: drop redundant function and marco declaration

with the patchset to add CSR atlas7 support, the below stuff
has no user now:
SIRFSOC_VA
sirfsoc_map_lluart
sirfsoc_map_scu

the related patches missed to drop them.

Signed-off-by: Barry Song <Baohua.Song@csr.com>
Signed-off-by: Olof Johansson <olof@lixom.net>