add lzop decompression support

Add lzop decompression support to the existing lzo bitstream handling
(think gzip versus zlib), and support it for uImage decompression if
CONFIG_LZO is enabled.

Lzop doesn't compress as good as gzip (~10% worse), but decompression
is very fast (~0.7s faster here on a slow ppc). The lzop decompression
code is based on Albin Tonnerre's recent ARM Linux lzo support patch.

Cc: albin.tonnerre@free-electrons.com
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
diff --git a/common/image.c b/common/image.c
index 6eaf41e..5cc3ab4 100644
--- a/common/image.c
+++ b/common/image.c
@@ -148,6 +148,7 @@
 	{	IH_COMP_BZIP2,	"bzip2",	"bzip2 compressed",	},
 	{	IH_COMP_GZIP,	"gzip",		"gzip compressed",	},
 	{	IH_COMP_LZMA,	"lzma",		"lzma compressed",	},
+	{	IH_COMP_LZO,	"lzo",		"lzo compressed",	},
 	{	-1,		"",		"",			},
 };