dt-bindings: PCI: fsl,imx6q-pcie: Add missing type for 'reset-gpio-active-high'

'reset-gpio-active-high' is missing a type definition and is not a common
property. The type is boolean.

Signed-off-by: Rob Herring <robh@kernel.org>
Acked-by: Richard Zhu <hongxing.zhu@nxp.com>
Link: https://lore.kernel.org/r/20220719215031.1875860-1-robh@kernel.org