arm: dts: socfpga: fix GIC PPI warning

[ Upstream commit 6d97d5aba08b26108f95dc9fb7bbe4d9436c769c ]

Fixes the warning "GIC: PPI13 is secure or misconfigured" by
changing the interrupt type from level_low to edge_raising

Signed-off-by: Philipp Puschmann <pp@emlix.com>
Signed-off-by: Dinh Nguyen <dinguyen@kernel.org>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>