phy: miphy28lp: Convert to devm_kcalloc and fix wrong sizof

Prefer devm_kcalloc over devm_kzalloc with multiply.
In additional, use sizeof(phy) is incorrect, fix it.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Acked-by: Gabriel Fernandez<gabriel.fernandez@linaro.org>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>