mips: octeon: Kconfig: Enable CONFIG_SYS_PCI_64BIT

Setting CONFIG_SYS_PCI_64BIT is needed for correct PCIe functionality on
MIPS Octeon.

Signed-off-by: Stefan Roese <sr@denx.de>

arch/mips/mach-octeon/Kconfig

@@ -55,6 +55,10 @@ config SYS_ICACHE_SIZE
 config SYS_ICACHE_LINE_SIZE
 	default 128
 
+config SYS_PCI_64BIT
+	bool
+	default y
+
 source "board/Marvell/octeon_ebb7304/Kconfig"
 
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