PCI: cpqphp: Use <linux/io.h> instead of <asm/io.h>

Use the preferred generic header file linux/io.h that already includes the
corresponding asm/io.h file.

Link: https://lore.kernel.org/r/20211013003145.1107148-2-kw@linux.com


Signed-off-by: Krzysztof Wilczyński <kw@linux.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Jonathan Derrick <jonathan.derrick@linux.dev>