rtas: Move FWNMI log space reservation to QEMU

This reverts commit 674d0d0cf66d4 ("rtas: Reserve space for FWNMI log")
which expanded the RTAS blob size to match the QEMU expectation about
the RTAS area available for FWNMI logs.

Instead, it relies on QEMU passing the "rtas-size" property and passes it
through untouched. This adds a check that QEMU allocated enough for
RTAS blob. This adds a fallback to the default 20 bytes "rtas-size" if
none specified by QEMU.

While we are here, replace 's" /rtas" find-node' with 'rtas-node' which
we just set above.

Reviewed-by: Greg Kurz <groug@kaod.org>
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
2 files changed