IMSM: move "validate_container_imsm" to be included in mdassemble

Commit 0c21b485e4beb7bcfe631412a231f7c1ea1067bc added new
function in imsm superswitch. This function should be
included in mdassemble.

Signed-off-by: Pawel Baldysiak <pawel.baldysiak@intel.com>
Signed-off-by: NeilBrown <neilb@suse.de>
Grow: fix that preventing resize of array to 32bit size.

If the request --size to --grow an array to is 32bits
(i.e. msb in bit 32) then mdadm make wrong choice and
uses ioctl instead of setting component_size via sysfs
and the change is ignored.

This is fixed by using correct casts.

Reported-and-tested-by: Killian De Volder <killian.de.volder@megasoft.be>
Signed-off-by: NeilBrown <neilb@suse.de>