arm64: dts: r8a7796: Add missing second pair of DMA names to MSIOF nodes

MSIOF0 and MSIOF1 are tied to two DMA controllers through two pairs of
DMA specifiers.  However, the second pair of corresponding DMA names was
missing.

Fixes: 80fab06e ("arm64: dts: r8a7796: Add all MSIOF nodes")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>