sys: Remove $FreeBSD$: one-line sh pattern

Remove /^\s*#[#!]?\s*\$FreeBSD\$.*$\n/

Remove IPI_IRQ_START and IPI_IRQ_END from the arm kernel config files.
These are unneeded with INTRNG.

Tag all armv7 kernels as such in their machine config line.

Transition all boards that support arm cortex CPUs to armv7. This
leaves two armv6 kernels in the tree. RPI-B, which uses the BCM2835
which has a ARM1176 core, and VERSATILEPB, which is a qemu board setup
around the time RPI-B went in. Copy std.armv6 to std.armv7, even
though that duplicates a lot of stuff. More work needs to be done to
sort out the duplication.

Differential Revision: https://reviews.freebsd.org/D12027

Remake support for SMP kernel on UP cpu:
- Use new option SMP_ON_UP instead of (mis)using specific CPU type.
By this, any SMP kernel can be compiled with SMP_ON_UP support.
- Enable runtime detection of CPU multiprocessor extensions only
if SMP_ON_UP option is used. In other cases (pure SMP or UP),
statically compile only required variant.
- Don't leak multiprocessor instructions to UP kernel.
- Correctly handle data cache write back to point of unification.
DCCMVAU is supported on all armv7 cpus.
- For SMP_ON_UP kernels, detect proper TTB flags on runtime.

Differential Revision: https://reviews.freebsd.org/D9133

Split CPU_CORTEXA into CPU_CORTEXA8, for the Cortex-A8, and CPU_CORTEXA_MP,
for later Cortex-A CPUs that support the Multiprocessor Extensions. This
will be needed to support both in a single GENERIC kernel while still
being able to only build for a single SoC.

Reviewed by: mmel
Relnotes: yes
Sponsored by: ABT Systems Ltd
Differential Revision: https://reviews.freebsd.org/D8138

Move ARM_L2_PIPT option to std.armv6 for all armv6 platforms.
Only L2 PIPT cache is supported for __ARM_ARCH >= 6.

In fact, this is just a pure proclamation as this option is used
only in armv4 specific files now.

Makeoption ARM_LITLE_ENDIAN does nothing. Remove it since it isn't
consistently used. It was a carry over from NetBSD that FreeBSD
doesn't use.

Change the virtual address used to not be 0xc0000000, the arm loader
doesn't handle this address.

Add support for the QEMU virt SoC. This is a SoC built depending on the
command line arguments passed in. It will then generate a dtb on the fly,
as such no dts will be added as it may be incorrect.

Relnotes: yes