[Coverity CID :198865]Null pointer dereferences in /drivers/usb/device/usb_dc_stm32.c

[aasthagr]

Static code scan issues seen in File: /drivers/usb/device/usb_dc_stm32.c
Category: Null pointer dereferences
Function: HAL_PCD_SetupStageCallback
Component: Drivers
CID: 198865
Please fix or provide comments to square it off in coverity in the link: https://scan9.coverity.com/reports.htm#v32951/p12996

[aasthagr]

*** CID 198865:  Null pointer dereferences  (NULL_RETURNS)
/drivers/usb/device/usb_dc_stm32.c: 966 in HAL_PCD_SetupStageCallback()
960     	struct usb_setup_packet *setup = (void *)usb_dc_stm32_state.pcd.Setup;
961     	struct usb_dc_stm32_ep_state *ep_state;
962     
963     	LOG_DBG("");
964     
965     	ep_state = usb_dc_stm32_get_ep_state(EP0_OUT); /* can't fail for ep0 */
>>>     CID 198865:  Null pointer dereferences  (NULL_RETURNS)
>>>     Dereferencing a null pointer "ep_state".
966     	ep_state->read_count = SETUP_SIZE;
967     	ep_state->read_offset = 0U;
968     	memcpy(&usb_dc_stm32_state.ep_buf[EP0_IDX],
969     	       usb_dc_stm32_state.pcd.Setup, ep_state->read_count);
970     
971     	if (ep_state->cb) {