ubifs: Fix wrong dirty space budget for dirty inode

hulk inclusion
category: bugfix
bugzilla: 187685, https://gitee.com/openeuler/kernel/issues/I5VVZX


CVE: NA

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

Each dirty inode should reserve 'c->bi.inode_budget' bytes in space
budget calculation. Currently, space budget for dirty inode reports
more space than what UBIFS actually needs to write.

Fixes: 1e51764a ("UBIFS: add new flash file system")
Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com>
Reviewed-by: Zhang Yi <yi.zhang@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>