PM: sleep: docs: Replace "diasble" with "disable"

Fix misspelling reported by codespell.

Signed-off-by: Sumanth Gavini <sumanth.gavini@yahoo.com>
Link: https://patch.msgid.link/20250523220238.455718-1-sumanth.gavini@yahoo.com


[ rjw: Subject rewrite ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>