Replace key_scan array of static pointers with inline function

Replace key_scan array of static pointers with inline function

The key_scan array is (was) an array that is setup as a reference to
members of itself that have static offsets. Replace this pointer
indirection with an inline function. This has also the advantage
that the compiler can inline the function and just just a direct
offset into the struct.

Replacing the implicit indirection with the pointer array with an
explicit indirection with the inline function also makes the code a
bit easier to follow.

Signed-off-by: Arne Schwabe <arne@rfc2549.org>
Acked-by: Gert Doering <gert@greenie.muc.de>
Message-Id: <20201023120259.29783-1-arne@rfc2549.org>
URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg21225.html
Signed-off-by: Gert Doering <gert@greenie.muc.de>