PCI: rcar: Add missing irq_dispose_mapping() into failpath

The rcar_pcie_get_resources() is another misnomer with a side effect.
The function does not only get resources, but also maps MSI IRQs via
irq_of_parse_and_map(). In case anything fails afterward, the IRQ
mapping must be disposed through irq_dispose_mapping() which is not
done.

This patch handles irq_of_parse_and_map() failures in by disposing
of the mapping in rcar_pcie_get_resources() as well as in probe.

Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Simon Horman <horms+renesas@verge.net.au>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Phil Edworthy <phil.edworthy@renesas.com>
Cc: Simon Horman <horms+renesas@verge.net.au>
Cc: Wolfram Sang <wsa@the-dreams.de>
Cc: linux-renesas-soc@vger.kernel.org