ARM: dts: am571x-idk: Fix gpios property to have the correct gpio number

ARM: dts: am571x-idk: Fix gpios property to have the correct  gpio number

commit d23f3839fe97d8dce03d ("ARM: dts: DRA7: Add pcie1 dt node for
EP mode") while adding the dt node for EP mode for DRA7 platform,
added rc node for am571x-idk and populated gpios property with
"gpio3 23". However the GPIO_PCIE_SWRST line is actually connected
to "gpio5 18". Fix it here. (The patch adding "gpio3 23" was tested
with another am57x board in EP mode which doesn't rely on reset from
host).

Cc: stable <stable@vger.kernel.org> # 4.14+
Fixes: d23f3839fe97d8dce03d ("ARM: dts: DRA7: Add pcie1 dt node for EP mode")
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>