meta-google: distro: Relax FIT_HASH_ALG

u-boot hashing does not confer any additional security in gBMC (we don't
sign the kernel and hashes live with the image). We can use a much
faster, but bus verifying algorithm instead. Ideally this would be
xxhash, but our u-boot is currently too old.

Change-Id: I796a4ed2db380eb86a9acbeae1f8a5e56cc8cb62
Signed-off-by: William A. Kennington III <wak@google.com>
diff --git a/meta-google/conf/distro/gbmc.conf b/meta-google/conf/distro/gbmc.conf
index bbba7ef..69fdda4 100644
--- a/meta-google/conf/distro/gbmc.conf
+++ b/meta-google/conf/distro/gbmc.conf
@@ -25,3 +25,6 @@
 SANITY_TESTED_DISTROS:append = " Debian-rodete \n debian-rodete \n "
 
 PREFERRED_PROVIDER_virtual/bmc-update ?= "inplace-gbmc-update"
+
+# Provides reasonable data integrity and faster than sha*
+FIT_HASH_ALG = "crc32"