MLK-20916-1: doc: imx: habv4: Fix typo in iMX6 and iMX7 encrypted boot guide

The set_priblob_bitfield command is enabled by selecting
CONFIG_CMD_PRIBLOB.

Fix typo in mx6_mx7_encrypted_boot.txt guide.

Signed-off-by: Breno Lima <breno.lima@nxp.com>
(cherry picked from commit 99f9696ef5f7d1c0f93b7d910e884890fca6c973)
1 file changed