bus: mhi: core: Add missing checks for MMIO register entries

As per documentation, fields marked as (required) in an MHI
controller structure need to be populated by the controller driver
before calling mhi_register_controller(). Ensure all required
pointers and non-zero fields are present in the controller before
proceeding with the registration.

Signed-off-by: Bhaumik Bhatt <bbhatt@codeaurora.org>
Reviewed-by: Jeffrey Hugo <jhugo@codeaurora.org>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/1615315490-36017-1-git-send-email-bbhatt@codeaurora.org
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

drivers/bus/mhi/core/init.c

@@ -861,12 +861,10 @@ int mhi_register_controller(struct mhi_controller *mhi_cntrl,
 	u32 soc_info;
 	int ret, i;
 
-	if (!mhi_cntrl)
-		return -EINVAL;
-
-	if (!mhi_cntrl->runtime_get || !mhi_cntrl->runtime_put ||
+	if (!mhi_cntrl || !mhi_cntrl->cntrl_dev || !mhi_cntrl->regs ||
+	    !mhi_cntrl->runtime_get || !mhi_cntrl->runtime_put ||
 	    !mhi_cntrl->status_cb || !mhi_cntrl->read_reg ||
-	    !mhi_cntrl->write_reg || !mhi_cntrl->nr_irqs)
+	    !mhi_cntrl->write_reg || !mhi_cntrl->nr_irqs || !mhi_cntrl->irq)
 		return -EINVAL;
 
 	ret = parse_config(mhi_cntrl, config);