initrdscripts: increase RAUC partition to 400MB
initrdscripts: increase RAUC partition to 400MB

The RAUC partitions were sized at 250MB each, based on the estimated
8-year growth curve for the nilrt-nxg bundle. The newer OneRT Base
System Image bundles are expected to be significantly larger, and 400MB
each is a better estimate for their 8-year growth.

Increase the size of each `nibootX` partition to 400MB, to accommodate
OneRT bundles.

Natinst-AZDO-ID: 1041635
Signed-off-by: Alex Stewart <04cdb2793e4fb0120cc30d1c823099f3862701f4@ni.com>
Rebased-by: Alex Stewart <04cdb2793e4fb0120cc30d1c823099f3862701f4@ni.com>

ni/meta-nilrt,ni/meta-nilrt,ni/meta-nilrt,ni/meta-nilrt,ni/meta-nilrt