drivers/mtd/nvmxip: Trigger post bind as probe on driver level

drivers/mtd/nvmxip: Trigger post bind as probe on driver level

Perform all the block device creation only once, after the driver itself
successfully bound. Do not do this in uclass post bind, as this might be
triggered multiple times. For example the ut_dm_host test triggers this
and triggers a memory leak that way, since there are now multiple block
devices created using the blk_create_devicef() .

To retain the old probe-on-boot behavior, set DM_FLAG_PROBE_AFTER_BIND
flag in uclass post_bind callback, so the driver model would probe the
driver at the right time.

Rename the function as well, to match similar functions in
other block-related subsystems, like the mmc one.

Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>