kernel: ext4: fix BUG in ext4_mb_new_inode_pa() due to overflow

An integer overflow flaw was found in the Linux kernel's ext4 filesystem. In ext4mbnewinodepa, when calculating the end position of ext4freeextent, the computation can overflow ext4lblkt uint32 to zero. This occurs with large logical block numbers near UINTMAX, causing a BUGON assertion failure a...