ACPI: button: Clean up printing messages

Replace the ACPI_DEBUG_PRINT() instance in button.c with an
acpi_handle_debug() call, drop the _COMPONENT and ACPI_MODULE_NAME()
definitions that are not used any more, drop the no longer needed
ACPI_BUTTON_COMPONENT definition from the headers and update the
documentation accordingly.

While at it, replace the direct printk() invocations with pr_info()
(that changes the excessive log level for some of them too) and drop
the unneeded PREFIX sybmbol definition from battery.c.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Hanjun Guo <guohanjun@huawei.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>