test/py: zynqmp_rpu: Fix tcminit mode value

Update the tcminit value to string and number both as per commit
342ccba5586a ("arm64: zynqmp: Fix tcminit mode value based on argv") and
also adds negative cases based on invalid command sequences.

Signed-off-by: Love Kumar <love.kumar@amd.com>
Link: https://lore.kernel.org/r/48f75577f6735a0d14105658e89b625d45537bb1.1731672024.git.love.kumar@amd.com
Signed-off-by: Michal Simek <michal.simek@amd.com>
1 file changed