fs: rename fsload command to load

When the generic filesystem load command "fsload" was written, I felt
that "load" was too generic of a name for it, since many other similar
commands already existed. However, it turns out that there is already
an "fsload" command, so that name cannot be used. Rename the new
"fsload" to plain "load" to avoid the conflict. At least anyone who's
used a Basic interpreter should feel familiar with the name!

Signed-off-by: Stephen Warren <swarren@nvidia.com>