ASoC: soc-core: tidyup for CONFIG_DMI

soc-core.c has 2 #ifdef CONFIG_DMI, but we can merge these.
OTOH, soc.h has dmi_longname, but it is needed if CONFIG_DMI was defined.
In other words, It is not needed if CONFIG_DMI was not defined.
This patch tidyup these.

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Link: https://lore.kernel.org/r/87eexbbhyy.wl-kuninori.morimoto.gx@renesas.com


Signed-off-by: Mark Brown <broonie@kernel.org>