[SPARC64]: Add proper header file extern for cmdline_memory_size.

Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/asm-sparc64/pgtable.h b/include/asm-sparc64/pgtable.h
index fd46dd6..46705ef 100644
--- a/include/asm-sparc64/pgtable.h
+++ b/include/asm-sparc64/pgtable.h
@@ -777,6 +777,8 @@
 extern void sun4v_register_fault_status(void);
 extern void sun4v_ktsb_register(void);
 
+extern unsigned long cmdline_memory_size;
+
 #endif /* !(__ASSEMBLY__) */
 
 #endif /* !(_SPARC64_PGTABLE_H) */