Merge patch series "bootm: Refactoring to reduce reliance on CMDLINE (part A)"

Merge patch series "bootm: Refactoring to reduce reliance on CMDLINE (part A)"

To quote the author:

It would be useful to be able to boot an OS when CONFIG_CMDLINE is
disabled. This could allow reduced code size.

Standard boot provides a way to handle programmatic boot, without
scripts, so such a feature is possible. The main impediment is the
inability to use the booting features of U-Boot without a command line.
So the solution is to avoid passing command arguments and the like to
code in boot/

A similar process has taken place with filesystems, for example, where
we have (somewhat) separate Kconfig options for the filesystem commands
and the filesystems themselves.

This series starts the process of refactoring the bootm logic so that
it can be called from standard boot without using the command line.
Mostly it removes the use of argc, argv and cmdtbl from the internal
logic.

Some limited tidy-up is included, but this is kept to smaller patches,
rather than trying to remove all #ifdefs etc. Some function comments
are added, however.

A simple programmatic boot is provided as a starting point.

This work will likely take many series, so this is just the start.

Size growth with this series for firefly-rk3288 (Thumb2) is:

       arm: (for 1/1 boards) all +23.0 rodata -49.0 text +72.0

This should be removed by:

   https://source.denx.de/u-boot/custodians/u-boot-dm/-/issues/11

but it is not included in this series as it is already large enough.

No functional change is intended in this series.

Changes in v3:
- Add a panic if programmatic boot fails
- Drop RFC tag

Changes in v2:
- Add new patch to adjust position of unmap_sysmem() in boot_get_kernel()
- Add new patch to obtain command arguments
- Fix 'boot_find_os' typo
- Pass in the command name
- Use the command table to provide the command name, instead of "bootm"