glsl: Round 0.95+ to 1 for texel colors

It improves SotC blooming. Suikoden seems to be fine too.

plugins/GSdx/res/glsl/tfx_fs.glsl

@@ -285,7 +285,10 @@ vec4 sample_color(vec2 st, float q)
 	t = c[0];
 #endif
 
-	return trunc(t * 255.0f);
+	// The 0.05f helps to fix the overbloom of sotc
+	// I think the issue is related to the rounding of texture coodinate. The linear (from fixed unit)
+	// interpolation could be slightly below the correct one.
+	return trunc(t * 255.0f + 0.05f);
 }
 
 vec4 tfx(vec4 T, vec4 C)

plugins/GSdx/res/glsl_source.h

@@ -1148,7 +1148,10 @@ static const char* tfx_fs_all_glsl =
 	"	t = c[0];\n"
 	"#endif\n"
 	"\n"
-	"	return trunc(t * 255.0f);\n"
+	"	// The 0.05f helps to fix the overbloom of sotc\n"
+	"	// I think the issue is related to the rounding of texture coodinate. The linear (from fixed unit)\n"
+	"	// interpolation could be slightly below the correct one.\n"
+	"	return trunc(t * 255.0f + 0.05f);\n"
 	"}\n"
 	"\n"
 	"vec4 tfx(vec4 T, vec4 C)\n"