PCI: rcar-pcie: Remove Gen2 designation from Kconfig

It appears that Gen2 is a misnomer for the R-Car PCIE driver
which also supports Gen 1 and Gen 3 SoCs. Accordingly, drop Gen 2
from the help text and Kconfig symbol.

Also, re-arange the Kconfig symbol name to use PCIE as the prefix.
This appears to be in keeping with other PCIE Kconfig symbols.

Reported-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Geert Uytterhoeven <geert+renesas@glider.be>
diff --git a/arch/arm/configs/multi_v7_defconfig b/arch/arm/configs/multi_v7_defconfig
index 2823490..f9fb719 100644
--- a/arch/arm/configs/multi_v7_defconfig
+++ b/arch/arm/configs/multi_v7_defconfig
@@ -119,7 +119,7 @@
 CONFIG_PCI_MVEBU=y
 CONFIG_PCI_TEGRA=y
 CONFIG_PCI_RCAR_GEN2=y
-CONFIG_PCI_RCAR_GEN2_PCIE=y
+CONFIG_PCIE_RCAR=y
 CONFIG_PCIEPORTBUS=y
 CONFIG_SMP=y
 CONFIG_NR_CPUS=16