common: spl: Kconfig: spelling fixes

Signed-off-by: Chris Packham <judge.packham@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/common/spl/Kconfig b/common/spl/Kconfig
index 37ecbc6..d175bb6 100644
--- a/common/spl/Kconfig
+++ b/common/spl/Kconfig
@@ -608,7 +608,7 @@
 	default "tpl/u-boot-with-tpl.bin" if TPL
 	default "u-boot.bin"
 	help
-	  Payload for SPL boot. For backward compability, default to
+	  Payload for SPL boot. For backward compatibility, default to
 	  u-boot.bin, i.e. RAW image without any header. In case of
 	  TPL, tpl/u-boot-with-tpl.bin. For new boards, suggest to
 	  use u-boot.img.