arm: meson: Tidy SoC information output

Write SoC instead of Soc. The Linux driver is not affected.

Fixes: f41d723b ("ARM: meson: display Amlogic SoC Information")
Signed-off-by: Andreas Färber <afaerber@suse.de>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>