soc/amd/common/psp_verstage: Remove arch/io.h

The arch include files are overshadowed by PSP verstage include files.
The reason is that psp_verstage implements its own set of inb() and
outb() functions, which use a runtime configurable IO base address
instead of a built time constant.

But this works at the moment only because of the order in which the
include files are added. Since that is very error prone, this patch
introduces another solution to the problem.

Signed-off-by: Maximilian Brune <maximilian.brune@9elements.com>
Change-Id: I16fa4a4cb5168024aaef30119e9aa8a34dbaacbe
Reviewed-on: https://review.coreboot.org/c/coreboot/+/86874
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Julius Werner <jwerner@chromium.org>

src/include/arch-generic/io.h

@@ -19,7 +19,12 @@
 #include <endian.h>
 #include <arch/mmio.h>
 
-#define __io(a)	(void *)(uintptr_t)(CONFIG_PCI_IOBASE + a)
+/*
+ * The memory address of a memory-mapped translator that lets the
+ * CPU communicate with peripheral devices over PCI I/O space.
+ */
+extern uintptr_t io_port_mmio_base;
+#define __io(a) (void *)(io_port_mmio_base + a)
 
 static inline void outb(uint8_t value, uint16_t port)
 {