ARM: convert PCI defines to variables

Convert PCIBIOS_MIN_IO and PCIBIOS_MIN_MEM to variables to allow
multi-platform builds. This also removes the requirement for a platform to
have a mach/hardware.h.

The default values for i/o and mem are 0x1000 and 0x01000000, respectively.
Per Arnd Bergmann, other values are likely to be incorrect, but this commit
does not try to address that issue.

Signed-off-by: Rob Herring <rob.herring@calxeda.com>
Acked-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
diff --git a/arch/arm/mach-shark/pci.c b/arch/arm/mach-shark/pci.c
index 89d175c..4aea637 100644
--- a/arch/arm/mach-shark/pci.c
+++ b/arch/arm/mach-shark/pci.c
@@ -37,8 +37,14 @@
 
 static int __init shark_pci_init(void)
 {
-	if (machine_is_shark())
-		pci_common_init(&shark_pci);
+	if (!machine_is_shark())
+		return;
+
+	pcibios_min_io = 0x6000;
+	pcibios_min_mem = 0x50000000;
+
+	pci_common_init(&shark_pci);
+
 	return 0;
 }