clk: en7523: Remove pcie prepare/unpreare callbacks for EN7581 SoC

Get rid of prepare and unpreare callbacks for PCIe clock since they can
be modeled as a reset line cosumed by the PCIe driver
(pcie-mediatek-gen3)

Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Tested-by: Zhengping Zhang <zhengping.zhang@airoha.com>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Link: https://lore.kernel.org/r/16df149975514d3030499c48fc1c64f090093595.1719485847.git.lorenzo@kernel.org


Signed-off-by: Stephen Boyd <sboyd@kernel.org>