LinuxKPI: cache.h add SMP_CACHE_BYTES

Add a definition for SMP_CACHE_BYTES and while here include sys/param.h
for CACHE_LINE_SIZE as otherwise code might not compile standalone.

Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
Reviewed by: hselasky
Differential Revision: https://reviews.freebsd.org/D30419