drm/amdgpu: Fix build with missing pm_suspend_target_state module export

Building a randconfig here triggered:

ERROR: modpost: "pm_suspend_target_state" [drivers/gpu/drm/amd/amdgpu/amdgpu.ko] undefined!

because the module export of that symbol happens in
kernel/power/suspend.c which is enabled with CONFIG_SUSPEND.

The ifdef guards in amdgpu_acpi_is_s0ix_supported(), however, test for
CONFIG_PM_SLEEP which is defined like this:

config PM_SLEEP
def_bool y
depends on SUSPEND || HIBERNATE_CALLBACKS

and that randconfig has:

# CONFIG_SUSPEND is not set
CONFIG_HIBERNATE_CALLBACKS=y

leading to the module export missing.

Change the ifdeffery to depend directly on CONFIG_SUSPEND.

Fixes: 5706cb3c910c ("drm/amdgpu: fix checking pmops when PM_SLEEP is not enabled")
Reviewed-by: Lijo Lazar <[e-mail]>
Signed-off-by: Borislav Petkov <[e-mail]>
Link: https://lkml.kernel.org/r/[e-mail]
Signed-off-by: Alex Deucher <[e-mail]>
Cc: [e-mail]

drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c

···
  */
 bool amdgpu_acpi_is_s0ix_active(struct amdgpu_device *adev)
 {
-#if IS_ENABLED(CONFIG_AMD_PMC) && IS_ENABLED(CONFIG_PM_SLEEP)
+#if IS_ENABLED(CONFIG_AMD_PMC) && IS_ENABLED(CONFIG_SUSPEND)
 	if (acpi_gbl_FADT.flags & ACPI_FADT_LOW_POWER_S0) {
 		if (adev->flags & AMD_IS_APU)
 			return pm_suspend_target_state == PM_SUSPEND_TO_IDLE;