microblaze: Use asm-generic/io.h

Using generic io.h will narrow down code duplication
in architecture io.h.

- define PCI_IOBASE
- remove non existing pci_io_base extern

Signed-off-by: Michal Simek <michal.simek@xilinx.com>

arch/microblaze/kernel/signal.c

@@ -216,7 +216,7 @@ static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
 		/* MS: I need add offset in page */
 		address += ((unsigned long)frame->tramp) & ~PAGE_MASK;
 		/* MS address is virtual */
-		address = virt_to_phys(address);
+		address = __virt_to_phys(address);
 		invalidate_icache_range(address, address + 8);
 		flush_dcache_range(address, address + 8);
 	}