RDMA/rtrs-srv: Do not unconditionally enable irq

RDMA/rtrs-srv: Do not unconditionally enable irq

When IO is completed, rtrs can be called in softirq context,
unconditionally enabling irq could cause panic.

To be on safe side, use spin_lock_irqsave and spin_unlock_irqrestore
instread.

Fixes: 9cb837480424 ("RDMA/rtrs: server: main functionality")
Signed-off-by: Jack Wang <jinpu.wang@ionos.com>
Signed-off-by: Florian-Ewald Mueller <florian-ewald.mueller@ionos.com>
Signed-off-by: Md Haris Iqbal <haris.iqbal@ionos.com>
Signed-off-by: Grzegorz Prajsner <grzegorz.prajsner@ionos.com>
Link: https://lore.kernel.org/r/20231120154146.920486-2-haris.iqbal@ionos.com
Signed-off-by: Leon Romanovsky <leon@kernel.org>