Most of the time when booting kernel prints a warning from
mm/page_alloc.c when pstore/ramoops is being initialized and ramoops is
not functional.
Fix this by moving ramopps node into reserved-memory block as described
in kernel documentation.
Fixes: 2964e5024c ("ipq806x: kernel ramoops storage for C2600/AD7200")
Signed-off-by: Filip Matijević <filip.matijevic.pz@gmail.com>