accel/ivpu: avoid build failure with CONFIG_PM=n

The usage count of struct dev_pm_info is an implementation detail that
is only available if CONFIG_PM is enabled, so printing it in a debug message
causes a build failure in configurations without PM:

In file included from include/linux/device.h:15,
                 from include/linux/pci.h:37,
                 from drivers/accel/ivpu/ivpu_pm.c:8:
drivers/accel/ivpu/ivpu_pm.c: In function 'ivpu_rpm_get_if_active':
drivers/accel/ivpu/ivpu_pm.c:254:51: error: 'struct dev_pm_info' has no member named 'usage_count'
  254 |                  atomic_read(&vdev->drm.dev->power.usage_count));
      |                                                   ^
include/linux/dev_printk.h:129:48: note: in definition of macro 'dev_printk'
  129 |                 _dev_printk(level, dev, fmt, ##__VA_ARGS__);            \
      |                                                ^~~~~~~~~~~
drivers/accel/ivpu/ivpu_drv.h:75:17: note: in expansion of macro 'dev_dbg'
   75 |                 dev_dbg((vdev)->drm.dev, "[%s] " fmt, #type, ##args);          \
      |                 ^~~~~~~
drivers/accel/ivpu/ivpu_pm.c:253:9: note: in expansion of macro 'ivpu_dbg'
  253 |         ivpu_dbg(vdev, RPM, "rpm_get_if_active count %d\n",
      |         ^~~~~~~~

The print message does not seem essential, so the easiest workaround is
to just remove it.

Fixes: c39dc151 ("accel/ivpu: Read clock rate only if device is up")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Stanislaw Gruszka <stanislaw.gruszka@linux.intel.com>
Signed-off-by: Stanislaw Gruszka <stanislaw.gruszka@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231027152633.528490-1-arnd@kernel.org