block/z2ram: Remove duplicate external declarations

Remove the external declarations for m68k_realnum_memory and m68k_memory,
which are already provided by <asm/setup.h>, to avoid conflicts later.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
diff --git a/drivers/block/z2ram.c b/drivers/block/z2ram.c
index 8b2a60c..27de5046 100644
--- a/drivers/block/z2ram.c
+++ b/drivers/block/z2ram.c
@@ -43,9 +43,6 @@
 #include <linux/zorro.h>
 
 
-extern int m68k_realnum_memory;
-extern struct mem_info m68k_memory[NUM_MEMINFO];
-
 #define Z2MINOR_COMBINED      (0)
 #define Z2MINOR_Z2ONLY        (1)
 #define Z2MINOR_CHIPONLY      (2)