firmware: xilinx: Remove zynqmp_pm_pinctrl_get_function()

There is no user for this interface that's why remove it.

Signed-off-by: Michal Simek <michal.simek@amd.com>
Link: https://lore.kernel.org/r/e52a415a004e28a43e6d08e9e22d9e8fef3737df.1702565618.git.michal.simek@amd.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>