param_t is only used as an offset and we have <1000 params, so an uint16_t
is enough.
This saves roughly 1KB of RAM. We only do that on NuttX because normal
integers have better performance in general.
Previously on amd64, this was even 64bits because it was an uintptr_t.

Unfortunately, lot's of whitespace changes, required to satisfy unspecified code style format errors.

Fixes shared memory locking bug and eliminates the need for an AppsProm driver to reserve a shared memory region.

There was the case where a param was changed on the Linux side but the
change did not get saved on the DSP side because the param was not in
the local list of changed params on the DSP side. On save, the param
index is now refreshed, and param_get is called on all params that have
changed. This is a hacky workaround but resolves the problem for now.

The locking seems to be broken, therefore refrain from using it.

Code that was previously out of tree that was #if 0, is now #ifdef __PX4_QURT.
These changes were required for flight using the qurt build.

Changes include code cleanup for shmem_posix.c.

Signed-off-by: Mark Charlebois <charlebm@gmail.com>

Signed-off-by: Mark Charlebois <charlebm@gmail.com>

This brings in many of the changes from the PX4 fork on ATLFLight.

Signed-off-by: Mark Charlebois <charlebm@gmail.com>

Code that was previously out of tree that was #if 0, is now #ifdef __PX4_QURT.
These changes were required for flight using the qurt build.

Changes include code cleanup for shmem_posix.c.

Signed-off-by: Mark Charlebois <charlebm@gmail.com>

Signed-off-by: Mark Charlebois <charlebm@gmail.com>

This brings in many of the changes from the PX4 fork on ATLFLight.

Signed-off-by: Mark Charlebois <charlebm@gmail.com>