cmd: correct kaslrseed description

The number of random bytes generated is hard coded as 8.
The command takes no argument.

Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
diff --git a/cmd/kaslrseed.c b/cmd/kaslrseed.c
index e0d3c7f..e9b0e3d 100644
--- a/cmd/kaslrseed.c
+++ b/cmd/kaslrseed.c
@@ -68,7 +68,7 @@
 }
 
 U_BOOT_LONGHELP(kaslrseed,
-	"[n]\n"
+	"\n"
 	"  - append random bytes to chosen kaslr-seed node\n");
 
 U_BOOT_CMD(