imx8qm_rom7720_a1: Remove unused function detail_board_ddr_info()

detail_board_ddr_info() is not used anywhere, so simply remove it.

This function is only used by Layerscape, not by i.MX.

This was detected by the following sparse warning:

board/advantech/imx8qm_rom7720_a1/imx8qm_rom7720_a1.c:110:6: warning: no previous
prototype for ‘detail_board_ddr_info’ [-Wmissing-prototypes]

Signed-off-by: Alifer Moraes <alifer.wsdm@gmail.com>
Reviewed-by: Oliver Graute <oliver.graute@kococonnector.com>
diff --git a/board/advantech/imx8qm_rom7720_a1/imx8qm_rom7720_a1.c b/board/advantech/imx8qm_rom7720_a1/imx8qm_rom7720_a1.c
index 2f97d5c..8bcbcc0 100644
--- a/board/advantech/imx8qm_rom7720_a1/imx8qm_rom7720_a1.c
+++ b/board/advantech/imx8qm_rom7720_a1/imx8qm_rom7720_a1.c
@@ -107,11 +107,6 @@
 	return 0;
 }
 
-void detail_board_ddr_info(void)
-{
-	puts("\nDDR    ");
-}
-
 /*
  * Board specific reset that is system reset.
  */