lib: sbi_scratch: remove owner from sbi_scratch_alloc_offset

The parameter owner of function sbi_scratch_alloc_offset() is never used.
The scratch memory is small. We should not use it for debug information in
future. Hence eliminate the parameter.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Reviewed-by: Xiang W <wxjstz@126.com>
Reviewed-by: Anup Patel <anup.patel@wdc.com>