phy: uniphier-pcie: Fix updating phy parameters

phy: uniphier-pcie: Fix updating phy parameters

The current driver uses a value from register TEST_O as the original
value for register TEST_I, though, the value is overwritten by "param",
so there is a bug that the original value isn't no longer used.

The value of TEST_O[7:0] should be masked with "mask", replaced with
"param", and placed in the bitfield TESTI_DAT_MASK as new TEST_I value.

Fixes: c6d9b1324159 ("phy: socionext: add PCIe PHY driver support")
Signed-off-by: Kunihiko Hayashi <hayashi.kunihiko@socionext.com>
Link: https://lore.kernel.org/r/1623037842-19363-1-git-send-email-hayashi.kunihiko@socionext.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>