powerpc/powermac: Fix symbol not declared warnings

1. ppc_override_l2cr and ppc_override_l2cr_value are only used in
   l2cr_init() function, remove them and used *l2cr directly.
2. has_l2cache is not used outside of the file, so mark it static and
   do not initialise statics to 0.

Fixes the following warnings:

  arch/powerpc/platforms/powermac/setup.c:73:5: warning: symbol
  'ppc_override_l2cr' was not declared. Should it be static?
  arch/powerpc/platforms/powermac/setup.c:74:5: warning: symbol
  'ppc_override_l2cr_value' was not declared. Should it be static?
  arch/powerpc/platforms/powermac/setup.c:75:5: warning: symbol
  'has_l2cache' was not declared. Should it be static?
Signed-off-by: Chen Lifu <chenlifu@huawei.com>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
[mpe: Unwrap printk string]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20221103070122.340773-1-chenlifu@huawei.com

arch/powerpc/platforms/powermac/setup.c

@@ -70,9 +70,7 @@
 
 #undef SHOW_GATWICK_IRQS
 
-int ppc_override_l2cr = 0;
-int ppc_override_l2cr_value;
-int has_l2cache = 0;
+static int has_l2cache;
 
 int pmac_newworld;
 
@@ -236,22 +234,16 @@ static void __init l2cr_init(void)
 			const unsigned int *l2cr =
 				of_get_property(np, "l2cr-value", NULL);
 			if (l2cr) {
-				ppc_override_l2cr = 1;
-				ppc_override_l2cr_value = *l2cr;
 				_set_L2CR(0);
-				_set_L2CR(ppc_override_l2cr_value);
+				_set_L2CR(*l2cr);
+				pr_info("L2CR overridden (0x%x), backside cache is %s\n",
+					*l2cr, ((*l2cr) & 0x80000000) ?
+					"enabled" : "disabled");
 			}
 			of_node_put(np);
 			break;
 		}
 	}
-
-	if (ppc_override_l2cr)
-		printk(KERN_INFO "L2CR overridden (0x%x), "
-		       "backside cache is %s\n",
-		       ppc_override_l2cr_value,
-		       (ppc_override_l2cr_value & 0x80000000)
-				? "enabled" : "disabled");
 }
 #endif