firmware: zynqmp: Probe driver before use

firmware: zynqmp: Probe driver before use

Probe the driver before use to ensure that the driver is always
available and the global data are valid. Initialize the global data
with zero and probe the driver if the global data are still zero. This
allows a usage of the firmware functions from other drivers with
arbitrary order between the drivers.

Signed-off-by: Stefan Herbrechtsmeier <stefan.herbrechtsmeier@weidmueller.com>
Link: https://lore.kernel.org/r/20220620163650.18756-2-stefan.herbrechtsmeier-oss@weidmueller.com
Signed-off-by: Michal Simek <michal.simek@amd.com>