PM: sleep: core: Fix indentation in dpm_wait_for_children()

The body of dpm_wait_for_children() is indented by 7 spaces instead of a
single TAB.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://patch.msgid.link/9c8ff2b103c3ba7b0d27bdc8248b05e3b1dc9551.1741776430.git.geert+renesas@glider.be


Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>