drm/amdgpu: fix link error for !PM_SLEEP

drm/amdgpu: fix link error for !PM_SLEEP

When power management is not enabled in the kernel build, the newly
added hibernation changes cause a link failure:

arm-linux-gnueabi-ld: drivers/gpu/drm/amd/amdgpu/amdgpu_drv.o: in function `amdgpu_pmops_thaw':
amdgpu_drv.c:(.text+0x1514): undefined reference to `pm_hibernate_is_recovering'

Make the power management code in this driver conditional on
CONFIG_PM and CONFIG_PM_SLEEP

Fixes: 530694f54dd5 ("drm/amdgpu: do not resume device in thaw for normal hibernation")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Link: https://lore.kernel.org/r/20250714081635.4071570-1-arnd@kernel.org
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>