Clean up diufb command definitions

The diufb command usage formatting is non-standard.  It was
made standard in preparation for larger command usage updates.

Signed-off-by: Peter Tyser <ptyser@xes-inc.com>

board/ads5121/ads5121_diu.c

@@ -101,7 +101,7 @@ int ads5121diu_init_show_bmp(cmd_tbl_t *cmdtp,
 
 U_BOOT_CMD(
 	diufb, CONFIG_SYS_MAXARGS, 1, ads5121diu_init_show_bmp,
-	"diufb init | addr - Init or Display BMP file\n",
+	"diufb - Init or Display BMP file\n",
 	"init\n    - initialize DIU\n"
 	"addr\n    - display bmp at address 'addr'\n"
 	);

board/freescale/mpc8610hpcd/mpc8610hpcd_diu.c

@@ -138,7 +138,7 @@ int mpc8610diu_init_show_bmp(cmd_tbl_t *cmdtp,
 
 U_BOOT_CMD(
 	diufb, CONFIG_SYS_MAXARGS, 1, mpc8610diu_init_show_bmp,
-	"diufb init | addr - Init or Display BMP file\n",
+	"diufb - Init or Display BMP file\n",
 	"init\n    - initialize DIU\n"
 	"addr\n    - display bmp at address 'addr'\n"
 	);