In a number of cases we have C files which rely on a chain of indirect
include paths to get <linux/string.h> to be included via <command.h>. To
facilitate cleaning up <command.h> make this code directly include
<linux/string.h>.

Signed-off-by: Tom Rini <trini@konsulko.com>

When the `optee hello' subcommand is called, the do_optee_hello_world_ta()
function passes a NULL pointer to the strcmp() function while verifying its
input argument, which results in the following crash:

  => optee hello
  "Synchronous Abort" handler, esr 0x96000010, far 0x0

Fix this by verifying the number of input arguments instead.

Fixes: e3cf80fbe02d ("cmd: Add support for optee commands")
Signed-off-by: Vincent Stehlé <vincent.stehle@arm.com>
Cc: Jens Wiklander <jens.wiklander@linaro.org>
Cc: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Cc: Tom Rini <trini@konsulko.com>
Cc: Jerome Forissier <jerome.forissier@linaro.org>
Cc: Venkatesh Yadav Abbarapu <venkatesh.abbarapu@amd.com>
Reviewed-by: Jerome Forissier <jerome.forissier@linaro.org>

Add the basic 'hello world ta' command which increment
of the value passed. This provides easy test for
establishing a session with OP-TEE TA and verify.

It includes following "hello world ta" subcommands:
optee hello; default value '0' is passed and gets incremented.
optee hello <value>; value to increment via OP-TEE HELLO
WORLD TA.

To enable the OP-TEE side HELLO WORLD example please refer
https://optee.readthedocs.io/en/latest/building/gits/optee_examples/optee_examples.html

Signed-off-by: Venkatesh Yadav Abbarapu <venkatesh.abbarapu@amd.com>
Reviewed-by: Jerome Forissier <jerome.forissier@linaro.org>