video: allow version string to be optional when using LOGO

The CONFIG_HIDE_LOGO_VERSION config can be used to disable putting the
U-Boot version string on top of the logo.

Signed-off-by: Tim Harvey <tharvey@gateworks.com>
diff --git a/README b/README
index 26d5ad2..e86934a 100644
--- a/README
+++ b/README
@@ -840,6 +840,9 @@
 			CONFIG_CONSOLE_EXTRA_INFO
 						additional board info beside
 						the logo
+			CONFIG_HIDE_LOGO_VERSION
+						do not display bootloader
+						version string
 
 		When CONFIG_CFB_CONSOLE_ANSI is defined, console will support
 		a limited number of ANSI escape sequences (cursor control,