gallium/aux/tgsi/tgsi_util.c: Fix warnings

tgsi_ureg.c: In function 'ureg_DECL_sampler':
tgsi_ureg.c:601:34: warning: comparison between signed and unsigned
integer expressions [-Wsign-compare]
       if (ureg->sampler[i].Index == nr)
                                  ^~
tgsi_ureg.c: In function 'validate':
tgsi_ureg.c:908:32: warning: unused parameter 'opcode' [-Wunused-
parameter]
 static void validate( unsigned opcode,
                                ^~~~~~
tgsi_ureg.c:909:32: warning: unused parameter 'nr_dst' [-Wunused-
parameter]
                       unsigned nr_dst,
                                ^~~~~~
tgsi_ureg.c:910:32: warning: unused parameter 'nr_src' [-Wunused-
parameter]
                       unsigned nr_src )
                                ^~~~~~
tgsi_ureg.c: In function 'emit_decls':
tgsi_ureg.c:1335:31: warning: comparison between signed and unsigned
integer expressions [-Wsign-compare]
       if (ureg->properties[i] != ~0)
                               ^~
tgsi_ureg.c: In function 'ureg_create':
tgsi_ureg.c:1594:18: warning: comparison between signed and unsigned
integer expressions [-Wsign-compare]
    for (i = 0; i < ARRAY_SIZE(ureg->properties); i++)
                  ^

v2: Replace VREND_UNUSED by UNUSED (Erik)

Reviewed-by: Erik Faye-Lund <erik.faye-lund@collabora.com>
Signed-off-by: Gert Wollny <gert.wollny@collabora.com>
Signed-off-by: Jakob Bornecrantz <jakob@collabora.com>

src/gallium/auxiliary/tgsi/tgsi_util.c

@@ -106,7 +106,7 @@ tgsi_util_set_src_register_swizzle(
 unsigned
 tgsi_util_get_full_src_register_sign_mode(
    const struct  tgsi_full_src_register *reg,
-   unsigned component )
+   UNUSED unsigned component )
 {
    unsigned sign_mode;