board-info: Use sysinfo_get()

board-info: Use sysinfo_get()

Replace uclass_first_device_err(UCLASS_SYSINFO, &dev) with sysinfo_get(&dev).
The board_info code may use sysinfo to print board information, so use the
sysinfo functions consistently. The sysinfo_get() is internally implemented
as return uclass_first_device_err(UCLASS_SYSINFO, &dev) anyway, so there is
no functional change.

Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
Cc: Marcel Ziswiler <marcel.ziswiler@toradex.com>
Cc: Simon Glass <sjg@chromium.org>
Reviewed-by: Simon Glass <sjg@chromium.org>