bus: mhi: core: Initialize bhie field in mhi_cntrl for RDDM capture

The bhie field in mhi_cntrl needs to be initialized to proper register
base in order to make mhi_rddm_prepare() to work. Otherwise,
mhi_rddm_prepare() will cause NULL pointer dereference.

Fixes: 6fdfdd2732 ("bus: mhi: core: Add support for downloading RDDM image during panic")
Reported-by: Hemant Kumar <hemantk@codeaurora.org>
Reviewed-by: Jeffrey Hugo <jhugo@codeaurora.org>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/20200324061050.14845-4-manivannan.sadhasivam@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/bus/mhi/core/init.c

@@ -979,7 +979,8 @@ int mhi_prepare_for_power_up(struct mhi_controller *mhi_cntrl)
 			goto bhie_error;
 		}
 
-		memset_io(mhi_cntrl->regs + bhie_off + BHIE_RXVECADDR_LOW_OFFS,
+		mhi_cntrl->bhie = mhi_cntrl->regs + bhie_off;
+		memset_io(mhi_cntrl->bhie + BHIE_RXVECADDR_LOW_OFFS,
 			  0, BHIE_RXVECSTATUS_OFFS - BHIE_RXVECADDR_LOW_OFFS +
 			  4);