mpc8548cds: Migrate CONFIG_INTERRUPTS to Kconfig

Only this platform sets this option, define it in the board Kconfig
file.

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/board/freescale/mpc8548cds/Kconfig b/board/freescale/mpc8548cds/Kconfig
index 723ead5..bb0a075 100644
--- a/board/freescale/mpc8548cds/Kconfig
+++ b/board/freescale/mpc8548cds/Kconfig
@@ -6,6 +6,9 @@
 config FSL_CADMUS
 	def_bool y
 
+config INTERRUPTS
+	def_bool y
+
 config SYS_BOARD
 	default "mpc8548cds"