arm64: Expand HWCAP2 to be 64 bit

There are more than 32 arm64 HWCAP2 values. Expand the macros to
include leading zeros and mark them as unsigned long.

Reviewed by: manu, imp, emaste
Sponsored by: Arm Ltd
Differential Revision: https://reviews.freebsd.org/D42378

(cherry picked from commit 0f0938800989dbf84a56c370db0b9379ee730a39)