Define global uma_memory variables

Use of the uma_memory_base and _size variables is very scattered.
Implementation of setup_uma_memory() will appear in each northbridge.

It should be possible to do this setup entirely in northbridge
code and get rid of the globals in a follow-up.

Change-Id: I07ccd98c55a6bcaa8294ad9704b88d7afb341456
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: http://review.coreboot.org/1204
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <patrick@georgi-clan.de>

src/northbridge/intel/i945/northbridge.c

@@ -68,9 +68,6 @@ static int get_pcie_bar(u32 *base, u32 *len)
 	return 0;
 }
 
-/* IDG memory */
-uint64_t uma_memory_base=0, uma_memory_size=0;
-
 static void add_fixed_resources(struct device *dev, int index)
 {
 	struct resource *resource;