hw_ep_prime sometimes fails if irq occurs while it rus on RT kernel.
to prevent local_irq_save should keep the function from irqs.

I am not sure where is the best to submit this patch, between RT and USB
community so sending to both. thanks.

Signed-off-by: Jeaho Hwang <redacted>
---
 drivers/usb/chipidea/udc.c | 31 +++++++++++++++++++++++++------
 1 file changed, 25 insertions(+), 6 deletions(-)

diff --git a/drivers/usb/chipidea/udc.c b/drivers/usb/chipidea/udc.c
index 5f35cdd2cf1d..a90498f17cc4 100644
--- a/drivers/usb/chipidea/udc.c
+++ b/drivers/usb/chipidea/udc.c

@@ -102,6 +102,9 @@ static int hw_ep_flush(struct ci_hdrc *ci, int num, int dir)
 {
 	int n = hw_ep_bit(num, dir);
 
+    /* From zynq-7000 TRM, It can take a long time
+     * so irq disable is not a good option for RT
+     */