sf: Use static for file-scope functions

Use static for file-scope functions and removed
them from header files.

Tested-by: Jagan Teki <jteki@openedev.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Signed-off-by: Jagan Teki <jteki@openedev.com>
2 files changed