ACPI: debug: Clean up acpi_aml_init()

The err_exit label in acpi_aml_init() is not used any more after
commit 9ec6dbfb ("ACPI: no need to check return value of
debugfs_create functions"), but the other label in there is not
necessary too, so rearrange the code to get rid of them both.

No intentional functional impact.

Fixes: 9ec6dbfb ("ACPI: no need to check return value of debugfs_create functions")
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>