drm/i915/dsi: use generic poll_timeout_us() instead of wait_for_us()

Prefer generic poll helpers over i915 custom helpers.

The sleep and timeout remain the same as for wait_for_us().

Reviewed-by: Jouni Högander <[e-mail]>
Link: https://lore.kernel.org/r/02e[e-mail]
Signed-off-by: Jani Nikula <[e-mail]>

drivers/gpu/drm/i915/display/icl_dsi.c

···
  *   Jani Nikula <[e-mail]>
  */
 
+#include <linux/iopoll.h>
+
 #include <drm/display/drm_dsc_helper.h>
 #include <drm/drm_atomic_helper.h>
 #include <drm/drm_fixed.h>
···
 static bool wait_for_header_credits(struct intel_display *display,
 				    enum transcoder dsi_trans, int hdr_credit)
 {
-	if (wait_for_us(header_credits_available(display, dsi_trans) >=
-			hdr_credit, 100)) {
+	int ret, available;
+
+	ret = poll_timeout_us(available = header_credits_available(display, dsi_trans),
+			      available >= hdr_credit,
+			      10, 100, false);
+	if (ret) {
 		drm_err(display->drm, "DSI header credits not released\n");
 		return false;
 	}
···
 static bool wait_for_payload_credits(struct intel_display *display,
 				     enum transcoder dsi_trans, int payld_credit)
 {
-	if (wait_for_us(payload_credits_available(display, dsi_trans) >=
-			payld_credit, 100)) {
+	int ret, available;
+
+	ret = poll_timeout_us(available = payload_credits_available(display, dsi_trans),
+			      available >= payld_credit,
+			      10, 100, false);
+	if (ret) {
 		drm_err(display->drm, "DSI payload credits not released\n");
 		return false;
 	}