board/beaglebone/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/beaglebone/genimage.cfg

@@ -12,6 +12,7 @@ image boot.vfat {
 			"am335x-bonegreen.dtb",
 		}
 	}
+
 	size = 16M
 }
 
@@ -22,7 +23,7 @@ image sdcard.img {
 	partition u-boot {
 		partition-type = 0xC
 		bootable = "true"
-                image = "boot.vfat"
+		image = "boot.vfat"
 	}
 
 	partition rootfs {