Unicorn is based on Qemu, which as a whole is licensed under only
version 2 of the GPL. Since socemu.py depends on Unicorn, socemu.py
needs to be licensed under a GPLv2-compatible license. socemu.py also
depends on bmo.py, so to ensure that the combined work can be
distributed under the GPLv2 bmo.py also needs to be licensed under a
GPLv2-compatible license.

Fix both of these issues by relicensing both socemu.py and bmo.py under
version 2 or later of the GNU GPL.

The reg_read() function already accounts for their special cases, so
there's no need to do so again.

Reuse the print and println functions from hello-aarch64 and remove
strnlen since we really don't need it.

The mode-switch binary failed to run in the emulator because it wasn't
initializing the stack pointer. It probably worked when running on real
hardware only because the stack pointer was already initialized there,
and this code simply reused it.

While we're initializing the stack pointer, we might as well initialize
everything else, too, so this change also initializes the
general-purpose registers, the link register, and the .data and .bss
sections of the binary (even though this code doesn't use them).

Add support for MT6750

It doesn't actually disassemble instructions yet--for now it only prints
them in hex and binary. This makes it easier to see patterns in the
instruction bits.

For some reason, Kiwi IRC can't connect to OFTC over TLS, so let's link
to the official OFTC web chat interface instead.

The Matrix bridge for the postmarketOS lowlevel channel has switched to
OFTC, so reflect this change in the Readme.

Always having to import md32_dis.py into a Python interpreter just to
disassemble one instruction got kind of annoying, so I added some basic
command-line functionality to the module.

The BROM log length gets set to zero when the log is either dumped out
the UART or read by one of the DL mode "read BROM log" commands
(0xDD/0xDF), so we only limit the the output length when the reported
length is non-zero. When the reported length is zero, we simply print
each character until we either hit the default max length (0x400 bytes,
the length of the BROM log buffer) or encounter a non-printable
character.