mesa: remove unused 'i' in dimensions_error_check()

Reviewed-by: Charmaine Lee <charmainel@vmware.com>
Reviewed-by: Marek Olšák <marek.olsak@amd.com>

src/mesa/main/texgetimage.c

@@ -913,7 +913,6 @@ dimensions_error_check(struct gl_context *ctx,
                        const char *caller)
 {
    const struct gl_texture_image *texImage;
-   int i;
 
    if (xoffset < 0) {
       _mesa_error(ctx, GL_INVALID_VALUE, "%s(xoffset = %d)", caller, xoffset);