w1: omap-hdq: print dev_err if irq flags are not cleared

If irq flags are not cleared for certain operations we
print an error message.

Since this should never occur in normal operation, this
patch is an optional safety-net and debugging tool.

Signed-off-by: H. Nikolaus Schaller <hns@goldelico.com>
Link: https://lore.kernel.org/r/2de305d3046c7281a7123347899abbaa64c54fb8.1590255176.git.hns@goldelico.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>