ARM: dts: imx6q-ba16: fix RTC interrupt level

ARM: dts: imx6q-ba16: fix RTC interrupt level

[ Upstream commit e6a4eedd49ce27c16a80506c66a04707e0ee0116 ]

RTC interrupt level should be set to "LOW". This was revealed by the
introduction of commit:

  f181987ef477 ("rtc: m41t80: use IRQ flags obtained from fwnode")

which changed the way IRQ type is obtained.

Fixes: 56c27310c1b4 ("ARM: dts: imx: Add Advantech BA-16 Qseven module")
Signed-off-by: Ian Ray <ian.ray@gehealthcare.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>