lib: make lib/842 decompress functions static

Make the do_index and do_op functions static.

They are used only internally by the 842 decompression function,
and should be static.
Reported-By: NFengguang Wu <fengguang.wu@intel.com>
Signed-off-by: NFengguang Wu <fengguang.wu@intel.com>
Signed-off-by: NDan Streetman <ddstreet@ieee.org>
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

lib/842/842_decompress.c

@@ -214,7 +214,7 @@ static int __do_index(struct sw842_param *p, u8 size, u8 bits, u64 fsize)
 	return 0;
 }
 
-int do_index(struct sw842_param *p, u8 n)
+static int do_index(struct sw842_param *p, u8 n)
 {
 	switch (n) {
 	case 2:
@@ -228,7 +228,7 @@ int do_index(struct sw842_param *p, u8 n)
 	}
 }
 
-int do_op(struct sw842_param *p, u8 o)
+static int do_op(struct sw842_param *p, u8 o)
 {
 	int i, ret = 0;