cmd: add test case for secure storage

1.mmc testsecurestorage to test secure storage
2.test secure storage in rpmb and test secure storage in
security partition when use emmc
3.test secure storage

cmd: add test case for secure storage

1.mmc testsecurestorage to test secure storage
2.test secure storage in rpmb and test secure storage in
security partition when use emmc
3.test secure storage in security partition when use nand

Change-Id: Id6f72893c002c5040cb1790051c9685911878df7
Signed-off-by: Hisping Lin <hisping.lin@rock-chips.com>

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