Only use sized format on IMG/ES3 for single channel.

src/gpu/gl/GrGpuGL.cpp

Index: src/gpu/gl/GrGpuGL.cpp
diff --git a/src/gpu/gl/GrGpuGL.cpp b/src/gpu/gl/GrGpuGL.cpp
index 97f2a114db48305c706c4910ac4acd1835b3863e..209edaa188462c4b093b66de9fa66b17b6c8f7ef 100644
--- a/src/gpu/gl/GrGpuGL.cpp
+++ b/src/gpu/gl/GrGpuGL.cpp
@@ -591,7 +591,8 @@ bool GrGpuGL::uploadTexData(const GrGLTexture::Desc& desc,
     // glTexImage2D for the internal format but will accept GL_R8.
     if (kNVIDIA_GrGLVendor == this->glContext().vendor() ||
         kImagination_GrGLVendor == this->glContext().vendor()) {
-        if (kGLES_GrGLStandard == this->glStandard() && this->glVersion() >= GR_GL_VER(3, 0)) {
+        if (kGLES_GrGLStandard == this->glStandard() && this->glVersion() >= GR_GL_VER(3, 0) &&
+            kAlpha_8_GrPixelConfig == dataConfig) {
            useSizedFormat = true;
         }
     }