[babl] babl: fix fixed to double conversions

[Øyvind "pippin" Kolås <ok src gnome org>]

commit e2ace5f161d65a00282c09cf2a13fc182bffc139
Author: Elle Stone <ellestone ninedegreesbelow com>
Date:   Sat Jun 9 19:18:43 2018 +0200

    babl: fix fixed to double conversions
    
    See issue #18 https://gitlab.gnome.org/GNOME/babl/issues/18

 babl/babl-icc.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/babl/babl-icc.c b/babl/babl-icc.c
index e8393e3..973da7f 100644
--- a/babl/babl-icc.c
+++ b/babl/babl-icc.c
@@ -165,12 +165,12 @@ static u8f8_t d_to_u8f8 (double value)
 
 static double s15f16_to_d (s15f16_t fix)
 {
-  return fix.integer + fix.fraction / 65535.0;
+  return fix.integer + fix.fraction / 65536.0;
 }
 
 static double u8f8_to_d (u8f8_t fix)
 {
-  return fix.integer + fix.fraction / 255.0;
+  return fix.integer + fix.fraction / 256.0;
 }
 
 static void write_s15f16 (ICC *state, int offset, double value)