meta: Abort texture upload if pixels == null and no pixel unpack buffer set
meta: Abort texture upload if pixels == null and no pixel unpack buffer set

in case of glTexImage{1,2,3}D(). Texture has already been allocated
at this point and we have no data to upload. With out this patch,
with create_pbo = true, we end up creating a temporary pbo and then
uploading uninitialzed texture data.

Signed-off-by: Anuj Phogat <e2026475996c48f0b97fd37e84129b3912980428@gmail.com>
Reviewed-by: Neil Roberts <822ec91a7ef82248fd36162ca8ac3283eba70848@linux.intel.com>

metora/MesaGLSLCompiler,metora/MesaGLSLCompiler,metora/MesaGLSLCompiler