rtc: i2c_rtc_emul: catch any write to the "reset" register

It's more natural that any write that happens to touch the reset
register should cause a reset, rather than just a write that starts at
that offset.
Reviewed-by: NSimon Glass <sjg@chromium.org>
Reviewed-by: NHeiko Schocher <hs@denx.de>
Signed-off-by: NRasmus Villemoes <rasmus.villemoes@prevas.dk>

drivers/rtc/i2c_rtc_emul.c

@@ -197,7 +197,8 @@ static int sandbox_i2c_rtc_xfer(struct udevice *emul, struct i2c_msg *msg,
 
 			/* Write the register */
 			memcpy(plat->reg + offset, ptr, len);
-			if (offset == REG_RESET)
+			/* If the reset register was written to, do reset. */
+			if (offset <= REG_RESET && REG_RESET < offset + len)
 				reset_time(emul);
 		}
 	}