net: pse-pd: pd692x0: reduce stack usage in pd692x0_setup_pi_matrix

The pd692x0_manager array in this function is really too big to fit on the
stack, though this never triggered a warning until a recent patch made
it slightly bigger:

drivers/net/pse-pd/pd692x0.c: In function 'pd692x0_setup_pi_matrix':
drivers/net/pse-pd/pd692x0.c:1210:1: error: the frame size of 1584 bytes is larger than 1536 bytes [-Werror=frame-larger-than=]

Change the function to dynamically allocate the array here.

Fixes: 35975401 ("net: pse-pd: pd692x0: Add support for PSE PI priority feature")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Kory Maincent <kory.maincent@bootlin.com>
Link: https://patch.msgid.link/20250709153210.1920125-1-arnd@kernel.org


Signed-off-by: Jakub Kicinski <kuba@kernel.org>