spl: add option to disable SPL banner output

Selecting this option will reduce SPL boot time by approx. 6 ms
(e. g. with 70 bytes long banner string at 115200 baud).
Signed-off-by: NAnatolij Gustschin <agust@denx.de>
Tested-by: NLukasz Majewski <lukma@denx.de>
Reviewed-by: NPhilipp Tomsich <philipp.tomsich@theobroma-systems.com>

common/spl/Kconfig

@@ -118,6 +118,13 @@ config SPL_SEPARATE_BSS
 	  location is used. Normally we put the device tree at the end of BSS
 	  but with this option enabled, it goes at _image_binary_end.
 
+config SPL_DISABLE_BANNER_PRINT
+	bool "Disable output of the SPL banner 'U-Boot SPL ...'"
+	help
+	  If this option is enabled, SPL will not print the banner with version
+	  info. Selecting this option could be useful to reduce SPL boot time
+	  (e.g. approx. 6 ms slower, when output on i.MX6 with 115200 baud).
+
 config SPL_DISPLAY_PRINT
 	bool "Display a board-specific message in SPL"
 	help

common/spl/spl.c

@@ -477,8 +477,10 @@ void preloader_console_init(void)
 
 	gd->have_console = 1;
 
+#ifndef CONFIG_SPL_DISABLE_BANNER_PRINT
 	puts("\nU-Boot SPL " PLAIN_VERSION " (" U_BOOT_DATE " - " \
 			U_BOOT_TIME ")\n");
+#endif
 #ifdef CONFIG_SPL_DISPLAY_PRINT
 	spl_display_print();
 #endif