RDMA/qedr: Fix srqs xarray initialization

There was a missing initialization for the srqs xarray.
SRQs xarray can also be called from irq context when searching
for an element and uses the xa_XXX_irq apis, therefore should
be initialized with IRQ flags.

Fixes: 9fd15987

 ("qedr: Convert srqidr to XArray")
Link: https://lore.kernel.org/r/20191027200451.28187-2-michal.kalderon@marvell.com
Signed-off-by: Ariel Elior <ariel.elior@marvell.com>
Signed-off-by: Michal Kalderon <michal.kalderon@marvell.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>