ARM: dts: r8a7791: consistently use single space before =

Consistently use a single space before a =.

This patch fixes instances where a tab is used instead.

This patch should not introduce any functional change.
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>