freedreno: fix bind_sampler_states when hwcso is NULL

src/gallium/tests/trivial/compute.c expects samplers to be cleaned
when the samplers list is NULL.
Like in radeon, the function behave like when the number of samplers
parameter is set to 0.

[small s/hwsco/hwcso/ typo fix]
Signed-off-by: Rob Clark <robclark@freedesktop.org>

src/gallium/drivers/freedreno/a2xx/fd2_texture.c

@@ -106,6 +106,9 @@ fd2_sampler_states_bind(struct pipe_context *pctx,
 		unsigned shader, unsigned start,
 		unsigned nr, void **hwcso)
 {
+	if (!hwcso)
+		nr = 0;
+
 	if (shader == PIPE_SHADER_FRAGMENT) {
 		struct fd_context *ctx = fd_context(pctx);
 

src/gallium/drivers/freedreno/a3xx/fd3_texture.c

@@ -149,6 +149,9 @@ fd3_sampler_states_bind(struct pipe_context *pctx,
 	uint16_t saturate_s = 0, saturate_t = 0, saturate_r = 0;
 	unsigned i;
 
+	if (!hwcso)
+		nr = 0;
+
 	for (i = 0; i < nr; i++) {
 		if (hwcso[i]) {
 			struct fd3_sampler_stateobj *sampler =

src/gallium/drivers/freedreno/a4xx/fd4_texture.c

@@ -150,6 +150,9 @@ fd4_sampler_states_bind(struct pipe_context *pctx,
 	uint16_t saturate_s = 0, saturate_t = 0, saturate_r = 0;
 	unsigned i;
 
+	if (!hwcso)
+		nr = 0;
+
 	for (i = 0; i < nr; i++) {
 		if (hwcso[i]) {
 			struct fd4_sampler_stateobj *sampler =