Fix libsysdecode vmprot flag decoding

Fix the regex used to find vmprot table entries and add the missing include.

This fixes kdumps output of PFLT arguments which would previously look like:
5202 101546 ktrace PFLT 0x5ae000 0x2<><invalid>2

They now display correctly:
5202 101546 ktrace PFLT 0x5ac000 0x2<VM_PROT_WRITE>

MFC after: 1 week