mboot64: pump up the amount of args per command

128 should be enough for anybody ;-)

Ugh, stuff controls the size of an on-stack array. Stack
is fairly large so we should be okay.

Runs fine...

Signed-off-by: Andrei Warkentin <andrey.warkentin@gmail.com>
mboot64: multiboot parameters support for 'bootelf'.

Paramaters are everything that comes after '--'.

Signed-off-by: Andrei Warkentin <andrey.warkentin@gmail.com>
mboot64: allow using env bootparams or config.h bootparams

Getting tired of frobbing strings around...

Signed-off-by: Andrei Warkentin <andrey.warkentin@gmail.com>
mboot64: allow default modules list.

In env or config.h.

Signed-off-by: Andrei Warkentin <andrey.warkentin@gmail.com>
mboot64: fix on-stack args array in main.c

What can I say? I am apparently OCD.

Signed-off-by: Andrei Warkentin <andrey.warkentin@gmail.com>