ACPI: remove "config ACPI_DEBUG_FUNC_TRACE"

Kconfig symbol ACPI_DEBUG_FUNC_TRACE was only used (through its
corresponding macro) in drivers/acpi/acpica/acmacros.h. That macro
was removed from that header in v3.8, with commit
86ff0e508f88eda6e479a897476026055831d2d8 ("ACPICA: Fix unmerged
acmacros.h divergences."), so ACPI_DEBUG_FUNC_TRACE can now be
removed too, as it is unused.

[rjw: Changelog]
Signed-off-by: Paul Bolle <[e-mail]>
Signed-off-by: Rafael J. Wysocki <[e-mail]>

drivers/acpi/Kconfig

···
 	  Documentation/kernel-parameters.txt to control the type and
 	  amount of debug output.
 
-config ACPI_DEBUG_FUNC_TRACE
-	bool "Additionally enable ACPI function tracing"
-	default n
-	depends on ACPI_DEBUG
-	help
-	  ACPI Debug Statements slow down ACPI processing. Function trace
-	  is about half of the penalty and is rarely useful.
-
 config ACPI_PCI_SLOT
 	bool "PCI slot detection driver"
 	depends on SYSFS