svga: minor code simplification in svga_texture_transfer_unmap()
svga: minor code simplification in svga_texture_transfer_unmap()

Use the tex variable instead of using svga_texture() again.

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

metora/MesaGLSLCompiler,metora/MesaGLSLCompiler,metora/MesaGLSLCompiler