cxl/pci: Remove endian confusion

cxl/pci: Remove endian confusion

readl() already handles endian conversion. That's the main difference
between readl() and __raw_readl(). This is benign on little-endian
systems, but big endian systems will end up byte-swabbing twice.

Fixes: 2905cb5236cb ("cxl/pci: Add (hopeful) error handling support")
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Link: https://lore.kernel.org/r/167030092025.4045167.10651070153523351093.stgit@dwillia2-xfh.jf.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>