phy: ti: j721e-wiz: Constify structs

phy: ti: j721e-wiz: Constify structs

clk_div_table and wiz_regmap_config are not modified and can therefore
be made const to allow the compiler to put them in read-only memory.

Before:
   text    data     bss     dec     hex filename
  20265    7044      64   27373    6aed drivers/phy/ti/phy-j721e-wiz.o

After:
   text    data     bss     dec     hex filename
  20649    6660      64   27373    6aed drivers/phy/ti/phy-j721e-wiz.o

Signed-off-by: Rikard Falkeborn <rikard.falkeborn@gmail.com>
Link: https://lore.kernel.org/r/20200524095516.25227-3-rikard.falkeborn@gmail.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>