f2fs: Add inline to f2fs_build_fault_attr() stub

mainline inclusion
from mainline-v6.10-rc1
commit 0d8968287a1cf7b03d07387dc871de3861b9f6b9
category: bugfix
bugzilla: https://gitee.com/src-openeuler/kernel/issues/IAGS16
CVE: CVE-2024-42160

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=0d8968287a1cf7b03d07387dc871de3861b9f6b9



--------------------------------

When building without CONFIG_F2FS_FAULT_INJECTION, there is a warning
from each file that includes f2fs.h because the stub for
f2fs_build_fault_attr() is missing inline:

  In file included from fs/f2fs/segment.c:21:
  fs/f2fs/f2fs.h:4605:12: warning: 'f2fs_build_fault_attr' defined but not used [-Wunused-function]
   4605 | static int f2fs_build_fault_attr(struct f2fs_sb_info *sbi, unsigned long rate,
        |            ^~~~~~~~~~~~~~~~~~~~~

Add the missing inline to resolve all of the warnings for this
configuration.

Fixes: 4ed886b187f4 ("f2fs: check validation of fault attrs in f2fs_build_fault_attr()")
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Signed-off-by: Zheng Zucheng <zhengzucheng@huawei.com>