phy: core: fix code style in devm_of_phy_provider_unregister

Documentation/process/coding-style.rst says:
"functions: they have the opening brace at the beginning of the next
line"

devm_of_phy_provider_unregister() function has opening brace at same
line, so fix it up.

Link: https://lore.kernel.org/r/20200629145010.122675-1-vkoul@kernel.org


Signed-off-by: Vinod Koul <vkoul@kernel.org>