mailbox: zynqmp: Extend timeout for getting observation bit

In case of fpga loading (which can be huge) 100ms is not enough. That's why
extend timeout 10 times to wait maximum 1s to get ACK back.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
diff --git a/drivers/mailbox/zynqmp-ipi.c b/drivers/mailbox/zynqmp-ipi.c
index 9483ed9..847a036 100644
--- a/drivers/mailbox/zynqmp-ipi.c
+++ b/drivers/mailbox/zynqmp-ipi.c
@@ -56,7 +56,7 @@
 
 	/* Wait until observation bit is cleared */
 	ret = wait_for_bit_le32(&ipi_int_apu->obs, IPI_BIT_MASK_PMU0, false,
-				100, false);
+				1000, false);
 
 	debug("%s, send %ld bytes\n", __func__, msg->len);
 	return ret;