cheatsheet: fix build command

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
diff --git a/cheatsheet.md b/cheatsheet.md
index 1f7f355..349c325 100644
--- a/cheatsheet.md
+++ b/cheatsheet.md
@@ -30,7 +30,7 @@
 ```
 $ cd openbmc
 $ TEMPLATECONF=meta-openbmc-machines/meta-openpower/meta-ibm/meta-palmetto/conf . oe-init-build-env
-$ obmc-phosphor-image
+$ bitbake obmc-phosphor-image
 ```
 
 ## Rebuilds & Reconfiguration