net: phy: mscc: make some arrays static const, makes object smaller

Don't populate arrays on the stack but instead them static const.
Makes the object code smaller by 280 bytes.

Before:
   text    data     bss     dec     hex filename
  24142    4368     192   28702    701e ./drivers/net/phy/mscc/mscc_ptp.o

After:
   text    data     bss     dec     hex filename
  23830    4400     192   28422    6f06 ./drivers/net/phy/mscc/mscc_ptp.o

(gcc version 10.2.0)

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Link: https://lore.kernel.org/r/20210801070155.139057-1-colin.king@canonical.com


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