Sometimes we need to set random rpmb key which is invisible
except for the device.
Generate the random key with hwcrypto interface and support
fastboot command "fastboot oem set-rpmb-random-key" to set it.
Test: build and boot on imx8q.
Change-Id: I44e1b6b091366d8ffceb1159fc65c17610ce5243
Signed-off-by: Ji Luo <ji.luo@nxp.com>