common: Drop linux/delay.h from common header

Move this uncommon header out of the common header.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/rtc/max6900.c b/drivers/rtc/max6900.c
index b351865..1192883 100644
--- a/drivers/rtc/max6900.c
+++ b/drivers/rtc/max6900.c
@@ -14,6 +14,7 @@
 #include <command.h>
 #include <rtc.h>
 #include <i2c.h>
+#include <linux/delay.h>
 
 #ifndef	CONFIG_SYS_I2C_RTC_ADDR
 #define	CONFIG_SYS_I2C_RTC_ADDR	0x50