boot/at91bootstrap3: fix checksum of license

Commit ca1604388a86d73c548c6e65eadd13f424685838 updated the checksum of
the tarball, but failed to update the one of main.c, which serves as a
license file.

Signed-off-by: Edgar Bonet <bonet@grenoble.cnrs.fr>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>

boot/at91bootstrap3/at91bootstrap3.hash

@@ -1,3 +1,3 @@
 # Locally calculated
 sha256  dd6a3c57c1c84fc3b18187bee3d139146a0e032dd1d8edea7b242730e0bc4fe1  at91bootstrap3-v3.9.3.tar.gz
-sha256  732b2a55b5905031d8ae420136ffb5f8889214865784386bf754cffab8d2bc6e  main.c
+sha256  fd7a1ce5719bb7abf5e289da2e0ea8c933af3ba0f6ad03dbdbd2b7f54a77498a  main.c