video: Split SPLASH_SCREEN_ALIGN from bmp command

The bmp command already has a way to centre the image. Using this CONFIG
option to also centre it makes it impossible to control where images are
placed on the screen. Drop the extra check.

Simplify the Kconfig file we are here.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/cmd/bmp.c b/cmd/bmp.c
index 45f4c12..d72a826 100644
--- a/cmd/bmp.c
+++ b/cmd/bmp.c
@@ -259,9 +259,7 @@
 	if (!ret) {
 		bool align = false;
 
-		if (CONFIG_IS_ENABLED(SPLASH_SCREEN_ALIGN) ||
-		    x == BMP_ALIGN_CENTER ||
-		    y == BMP_ALIGN_CENTER)
+		if (x == BMP_ALIGN_CENTER || y == BMP_ALIGN_CENTER)
 			align = true;
 
 		ret = video_bmp_display(dev, addr, x, y, align);