include: Move bits related defines and macros to sbi_bitops.h

The right location for all bits related defines and macros is
sbi_bitops.h hence this patch. With this patch, the sbi_bits.h
is redundant so we remove it.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>