all: use a more straightforward return value

Change-Id: I09cd23c40278ebbccf8a0361e2b968df0d3963c5
Reviewed-on: https://go-review.googlesource.com/c/image/+/653195
Auto-Submit: Ian Lance Taylor <iant@google.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>

 font/sfnt/truetype.go | 2 +-
 webp/decode.go        | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/font/sfnt/truetype.go b/font/sfnt/truetype.go
index 0d0b309..92a15fd 100644
--- a/font/sfnt/truetype.go
+++ b/font/sfnt/truetype.go
@@ -77,7 +77,7 @@ func parseLoca(src *source, loca table, glyfOffset uint32, indexToLocFormat bool
 			locations[i] = 2*uint32(u16(buf[2*i:])) + glyfOffset
 		}
 	}
-	return locations, err
+	return locations, nil
 }
 
 // https://www.microsoft.com/typography/OTSPEC/glyf.htm says that "Each
diff --git a/webp/decode.go b/webp/decode.go
index e211c7d..0df3c67 100644
--- a/webp/decode.go
+++ b/webp/decode.go
@@ -261,7 +261,7 @@ func Decode(r io.Reader) (image.Image, error) {
 	if err != nil {
 		return nil, err
 	}
-	return m, err
+	return m, nil
 }
 
 // DecodeConfig returns the color model and dimensions of a WEBP image without