Remove vnode creation from zfs_create_fs() and zfs_create_share_dir()
as a vnode is not needed here.

Inspired by FreeBSD r253603.
Change zfs to vcache.
- zfs_loadvnode() is based on zfs_zget() plus zfs_znode_alloc().
Make getver() into a constant function since Version Register (%ver)
is read only and its value is constant.

This change reduces multipule %ver reads to one in the functions
which uses a number of CPU_IS_* macros.
Use GETVER_CPU_* macros.
Add missing A80 intr defs
A80 gpio and watchdog support