svga: remove duplicated variable in svga_texture_transfer_map()
svga: remove duplicated variable in svga_texture_transfer_map()

tex was already declared at the function body scope.

Reviewed-by: Neha Bhende <faec1a32a2d2624ef91f92ce8eed261ff4162c00@vmware.com>

metora/MesaGLSLCompiler,metora/MesaGLSLCompiler,metora/MesaGLSLCompiler