crypto: xilinx: prevent probing on non-xilinx hardware

The zynqmp-sha driver is always loaded and register its algorithm even on
platform which do not have the proper hardware.
This lead to a stacktrace due to zynqmp-sha3-384 failing its crypto
self tests.
So check if hardware is present via the firmware API call get_version.

While at it, simplify the platform_driver by using module_platform_driver()

Furthermore the driver should depend on ZYNQMP_FIRMWARE since it cannot
work without it.

Fixes: 7ecc3e34

 ("crypto: xilinx - Add Xilinx SHA3 driver")
Signed-off-by: Corentin Labbe <clabbe@baylibre.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>