CBMEM: Define cbmem_top() just once for x86

It is expected this will always be a casted get_top_of_ram() call
on x86, no reason to do that under chipset.

Change-Id: I3a49abe13ca44bf4ca1e26d1b3baf954bc5a29b7
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: http://review.coreboot.org/3972
Tested-by: build bot (Jenkins)
Reviewed-by: Aaron Durbin <adurbin@google.com>
diff --git a/src/northbridge/intel/haswell/northbridge.c b/src/northbridge/intel/haswell/northbridge.c
index 9f02734..ac61ca4 100644
--- a/src/northbridge/intel/haswell/northbridge.c
+++ b/src/northbridge/intel/haswell/northbridge.c
@@ -535,14 +535,14 @@
 	MCHBAR32(0x5500) = 0x00100001;
 }
 
-void *cbmem_top(void)
+unsigned long get_top_of_ram(void)
 {
 	u32 reg;
 
 	/* The top the reserve regions fall just below the TSEG region. */
 	reg = pci_read_config32(dev_find_slot(0, PCI_DEVFN(0, 0)), TSEG);
 
-	return (void *)(reg & ~((1 << 20) - 1));
+	return (reg & ~((1 << 20) - 1));
 }
 
 static void northbridge_enable(device_t dev)