trivial: Fix misspelling of "firmware" in acpi_memhotplug.c

Fix misspelling of "firmware" in acpi_memhotplug.c

It's spelled "firmware".
Signed-off-by: NNick Andrew <nick@nick-andrew.net>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>

drivers/acpi/acpi_memhotplug.c

@@ -20,7 +20,7 @@
  *
  *
  * ACPI based HotPlug driver that supports Memory Hotplug
- * This driver fields notifications from firmare for memory add
+ * This driver fields notifications from firmware for memory add
  * and remove operations and alerts the VM of the affected memory
  * ranges.
  */