accel/ivpu: Do not use irqsave in ivpu_ipc_dispatch

ivpu_ipc_dispatch is always called with irqs disabled. Add lockdep
assertion and remove unneeded _irqsave/_irqrestore.

Signed-off-by: Stanislaw Gruszka <stanislaw.gruszka@linux.intel.com>
Signed-off-by: Jacek Lawrynowicz <jacek.lawrynowicz@linux.intel.com>
Reviewed-by: Jeffrey Hugo <quic_jhugo@quicinc.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231113170252.758137-3-jacek.lawrynowicz@linux.intel.com