[PATCH v1] PM: hibernate: Fix pm_hibernation_mode_is_suspend() build breakage

["Rafael J. Wysocki" <rafael@kernel.org>]

From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Commit 495c8d35035e ("PM: hibernate: Add pm_hibernation_mode_is_suspend()")
that introduced pm_hibernation_mode_is_suspend() did not define it in
the case when CONFIG_HIBERNATION is unset, but CONFIG_SUSPEND is set.

Subsequent commit 0a6e9e098fcc ("drm/amd: Fix hybrid sleep") made the
amdgpu driver use that function which led to kernel build breakage in
the case mentioned above [1].

Address this by using appropriate #ifdeffery aroung the definition of
pm_hibernation_mode_is_suspend().

Fixes: 0a6e9e098fcc ("drm/amd: Fix hybrid sleep")
Reported-by: KernelCI bot <bot@kernelci.org> 
Closes: https://groups.io/g/kernelci-results/topic/regression_pm_testing/115439919 [1]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
 include/linux/suspend.h |    8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

--- a/include/linux/suspend.h
+++ b/include/linux/suspend.h
@@ -276,7 +276,6 @@ extern void arch_suspend_enable_irqs(voi
 
 extern int pm_suspend(suspend_state_t state);
 extern bool sync_on_suspend_enabled;
-bool pm_hibernation_mode_is_suspend(void);
 #else /* !CONFIG_SUSPEND */
 #define suspend_valid_only_mem	NULL
 
@@ -289,7 +288,6 @@ static inline bool pm_suspend_via_firmwa
 static inline bool pm_resume_via_firmware(void) { return false; }
 static inline bool pm_suspend_no_platform(void) { return false; }
 static inline bool pm_suspend_default_s2idle(void) { return false; }
-static inline bool pm_hibernation_mode_is_suspend(void) { return false; }
 
 static inline void suspend_set_ops(const struct platform_suspend_ops *ops) {}
 static inline int pm_suspend(suspend_state_t state) { return -ENOSYS; }
@@ -420,6 +418,12 @@ static inline int hibernate_quiet_exec(i
 }
 #endif /* CONFIG_HIBERNATION */
 
+#if defined(CONFIG_HIBERNATION) && defined(CONFIG_SUSPEND)
+bool pm_hibernation_mode_is_suspend(void);
+#else
+static inline bool pm_hibernation_mode_is_suspend(void) { return false; }
+#endif
+
 int arch_resume_nosmt(void);
 
 #ifdef CONFIG_HIBERNATION_SNAPSHOT_DEV