i2c: rzg2l: include u-boot/schedule.h

This TU currently relies on getting a declaration of schedule()
through some nested include. Include the proper header directly.

Signed-off-by: Rasmus Villemoes <ravi@prevas.dk>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Stefan Roese <sr@denx.de>
diff --git a/drivers/i2c/rz_riic.c b/drivers/i2c/rz_riic.c
index 5f3f8d1..f292c82 100644
--- a/drivers/i2c/rz_riic.c
+++ b/drivers/i2c/rz_riic.c
@@ -14,6 +14,7 @@
 #include <linux/bitops.h>
 #include <linux/delay.h>
 #include <reset.h>
+#include <u-boot/schedule.h>
 #include <wait_bit.h>
 
 #define RIIC_ICCR1	0x00