board/beagleboardx15/genimage.cfg: beautify file

Beatify this genimage .cfg file to have consistency with all genimage .cfg
files in Buildroot.

Signed-off-by: Giulio Benetti <giulio.benetti@benettiengineering.com>
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>

board/beagleboardx15/genimage.cfg

@@ -5,6 +5,7 @@ image boot.vfat {
 			"u-boot.img"
 		}
 	}
+
 	size = 4M
 }
 
@@ -15,7 +16,7 @@ image sdcard.img {
 	partition u-boot {
 		partition-type = 0xC
 		bootable = "true"
-                image = "boot.vfat"
+		image = "boot.vfat"
 	}
 
 	partition rootfs {