firmware: xilinx: Move EXPORT_SYMBOL_GPL next to zynqmp_pm_feature definition

As mentioned in Documentation/process/coding-style.rst:
In source files, separate functions with one blank line. If the function
is exported, the **EXPORT** macro for it should follow immediately after
the closing function brace line.

So inline with guideline move zynqmp_pm_feature export symbol after its
definition.

Signed-off-by: Rajan Vaja <rajan.vaja@xilinx.com>
Signed-off-by: Radhey Shyam Pandey <radhey.shyam.pandey@amd.com>
Link: https://lore.kernel.org/r/1698348238-2320426-1-git-send-email-radhey.shyam.pandey@amd.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>