PCI: cpcihp: Remove unused .get_power() and .set_power()

PCI: cpcihp: Remove unused .get_power() and .set_power()

The .get_power() and .set_power() function pointers in struct
cpci_hp_controller_ops were declared but never implemented by any
driver.

Thus, to improve code readability and reduce resource usage,
remove these pointers and the code that has never been used.

Link: https://lore.kernel.org/r/20250217185638.398925-1-trintaeoitogc@gmail.com
Signed-off-by: Guilherme Giacomo Simoes <trintaeoitogc@gmail.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
[kwilczynski: commit log]
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>