IB/qib: fix spelling mistake "colescing" -> "coalescing"

There is a spelling mistake in the module description text, fix it.

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Reviewed-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>