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
A80 MMC support. Works for SD card slot on Cubie4, but not eMMC yet.
add hummingbird A31 and allwinner A80 board types
add A80 led and mmc0detect gpios
A80 I2C support
User-triggerable kmem_alloc(0).

Ok martin@ christos@

User
A80 EHCI and OHCI support
Partial A80 GMAC support. Needs help from PMU to power it up still.
enable awge, axp22x
- Fix comment which was no longer accurate after previous change to move
  from in_pcbconnect -> in6_pcbsetport.
A80 DMA controller support
fix non-A80 builds
Memset the whole cfg array, not piecemeal because otherwise you'll end
up with random data depending on the options set.
XXX: pullup 7
Add compatibility for pre MIDMAGIC a.out binaries (with COMPAT_NOMID)
Oldzmagic binaries need "sysctl -w vm.user_va0_disable=0"
Add COMPAT_NOMID