ARM: shmobile: defconfig: Enable missing PCIE_RCAR dependency

PCIE_RCAR is no longer enabled, as it now has a dependency on
PCI_MSI_IRQ_DOMAIN instead of selecting PCI_MSI and PCI_MSI_IRQ_DOMAIN.
Fix this by explicitly enabling PCIE_RCAR in shmobile_defconfig.

Fixes: 3ee80364 ("PCI/MSI: irqchip: Fix PCI_MSI dependencies")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>