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>

src/arch/x86/boot/cbmem.c

@@ -55,4 +55,12 @@ unsigned long __attribute__((weak)) get_top_of_ram(void)
 }
 #endif /* !__PRE_RAM__ */
 
-#endif
+#else
+
+void *cbmem_top(void)
+{
+	/* Top of cbmem is at lowest usable DRAM address below 4GiB. */
+	return (void *)get_top_of_ram();
+}
+
+#endif /* DYNAMIC_CBMEM */

src/mainboard/emulation/qemu-i440fx/memory.c

@@ -44,11 +44,3 @@ unsigned long get_top_of_ram(void)
 {
 	return qemu_get_memory_size() * 1024;
 }
-
-#if CONFIG_DYNAMIC_CBMEM
-void *cbmem_top(void)
-{
-	/* Top of cbmem is at lowest usable DRAM address below 4GiB. */
-	return (void *)get_top_of_ram();
-}
-#endif

src/northbridge/intel/haswell/northbridge.c

@@ -535,14 +535,14 @@ static void northbridge_init(struct device *dev)
 	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)

src/northbridge/intel/haswell/raminit.c

@@ -202,12 +202,6 @@ void sdram_initialize(struct pei_data *pei_data)
 	report_memory_config();
 }
 
-void *cbmem_top(void)
-{
-	/* Top of cbmem is at lowest usable DRAM address below 4GiB. */
-	return (void *)get_top_of_ram();
-}
-
 unsigned long get_top_of_ram(void)
 {
 	/*