The kernel will never map the first page, so any symbols in that
range cannot refer to addresses. Some third-party assembly files
define internal constants which appear in their symbol table.
Avoiding the lookup for those symbols avoids replacing small offsets
with those symbols during disassembly.
Reported by: Anton Rang <rang%acm.org>
Reviewed by: Anton Rang <rang%acm.org>, markj
MFC after: 2 weeks
Sponsored by: Dell EMC Isilon
Differential Revision: https://reviews.freebsd.org/D26895
8310609fdd