mm/compaction: fix UBSAN shift-out-of-bounds warning

In the Linux kernel, the following vulnerability has been resolved:

mm/compaction: fix UBSAN shift-out-of-bounds warning

syzkaller reported a UBSAN shift-out-of-bounds warning of (1UL << order)

in isolate_freepages_block(). The bogus compound_order can be any value

because it is union with flags. Add back the MAX_PAGE_ORDER check to fix

the warning.