Bump LMB_MAX_REGIONS default to 16

Since commit 06d514d7 ("lmb: consider EFI memory map") the EFI regions
are also pushed into the lmb if EFI_LOADER is enabled (which is by
default on most system). Which can cause the number of entries to go
over the maximum as it's default is only 8.

Specifically i ran into this case on an TI am62 which has an fdt with
4 reserved regions (in practice 3 lmb entries due to adjecent ranges).

As this is likely to impact more devices bump the default max
regions to 16 so there is a bit more slack.

Fixes: 06d514d7 ("lmb: consider EFI memory map")
Link: https://bugzilla.opensuse.org/show_bug.cgi?id=1207562


Reviewed-by: Francesco Dolcini <francesco.dolcini@toradex.com>
Signed-off-by: Sjoerd Simons <sjoerd@collabora.com>
Signed-off-by: Michal Suchanek <msuchanek@suse.de>
[trini: collect tags from the other equivalent patch]