UPSTREAM: f2fs: check validation of fault attrs in f2fs_build_fault_attr()

- It missed to check validation of fault attrs in parse_options(),
let's fix to add check condition in f2fs_build_fault_attr().
- Use f2fs_build_fault_attr() in __sbi_store() to clean up code.

Change-Id: I34e10cbf62084a0a16db42960a12668f589ff222
Signed-off-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
(cherry picked from commit 4ed886b1)