ARM: multi_v7_defconfig: Enable DMA for Renesas serial ports

DMA for (H)SCIF(A|B) serial ports on Renesas R-Car Gen2 and RZ/G1 SoCs
is considered stable, hence enable it by default.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>

arch/arm/configs/multi_v7_defconfig

@@ -330,6 +330,7 @@ CONFIG_SERIAL_IMX_CONSOLE=y
 CONFIG_SERIAL_SH_SCI=y
 CONFIG_SERIAL_SH_SCI_NR_UARTS=20
 CONFIG_SERIAL_SH_SCI_CONSOLE=y
+CONFIG_SERIAL_SH_SCI_DMA=y
 CONFIG_SERIAL_MSM=y
 CONFIG_SERIAL_MSM_CONSOLE=y
 CONFIG_SERIAL_VT8500=y