cpu_to_be16() returns __be16 value but the driver uses u16 and that's
incorrect. Fix it by using __be16 as the data type of bdf_be variable.

The issue was spotted by the below sparse warning:

sparse warnings: (new ones prefixed by >>)
>> drivers/pci/controller/dwc/pcie-qcom.c:1305:30: sparse: sparse: incorrect type in initializer (different base types) @@     expected unsigned short [usertype] bdf_be @@     got restricted __be16 [usertype] @@
   drivers/pci/controller/dwc/pcie-qcom.c:1305:30: sparse:     expected unsigned short [usertype] bdf_be
   drivers/pci/controller/dwc/pcie-qcom.c:1305:30: sparse:     got restricted __be16 [usertype]

Link: https://lore.kernel.org/r/20211130080924.266116-1-manivannan.sadhasivam@linaro.orgReported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Krzysztof Wilczyński <kw@linux.com>