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-versatile/pci.c b/arch/arm/mach-versatile/pci.c
index 13c7e5f..7848a17 100644
--- a/arch/arm/mach-versatile/pci.c
+++ b/arch/arm/mach-versatile/pci.c
@@ -311,6 +311,9 @@
 
 void __init pci_versatile_preinit(void)
 {
+	pcibios_min_io = 0x44000000;
+	pcibios_min_mem = 0x50000000;
+
 	__raw_writel(VERSATILE_PCI_MEM_BASE0 >> 28, PCI_IMAP0);
 	__raw_writel(VERSATILE_PCI_MEM_BASE1 >> 28, PCI_IMAP1);
 	__raw_writel(VERSATILE_PCI_MEM_BASE2 >> 28, PCI_IMAP2);