[hgiMetal] Fixed texture resource storage mode

Restored the earlier behavior of allocating textures
with MTLResourceStorageModePrivate. This is the preferred
mode for best performance and compatibility across different
Metal implementations.

This regression had been introduced inadvertently as part of
enabling imaging for Apple embedded systems.

Fixes PixarAnimationStudios#3470

(Internal change: 2352441)

pxr/imaging/hgiMetal/texture.mm

@@ -23,10 +23,6 @@
     MTLResourceOptions resourceOptions = MTLResourceStorageModePrivate;
     MTLTextureUsage usage = MTLTextureUsageShaderRead;
 
-    if (desc.initialData && desc.pixelsByteSize > 0) {
-        resourceOptions = hgi->GetCapabilities()->defaultStorageMode;
-    }
-
     MTLPixelFormat mtlFormat = HgiMetalConversions::GetPixelFormat(
         desc.format, desc.usage);