staging: vt6656: limit reg output to block size

staging: vt6656: limit reg output to block size

vnt_control_out appears to fail when BBREG is greater than 64 writes.

Create new function that will relay an array in no larger than
the indicated block size.

It appears that this command has always failed but was ignored by
driver until the introduction of error checking.

Cc: stable <stable@vger.kernel.org> # v5.3+
Signed-off-by: Malcolm Priestley <tvboxspy@gmail.com>
Link: https://lore.kernel.org/r/a41f0601-df46-ce6e-ab7c-35e697946e2a@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>