Revert "drm/i915: Force clean compilation with -Werror"

This reverts commit 118182e9.

It's causing too much trouble when compile-testing for non-i915 folks.

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>

drivers/gpu/drm/i915/Kconfig

@@ -71,11 +71,3 @@ config DRM_I915_PRELIMINARY_HW_SUPPORT
 	  option changes the default for that module option.
 
 	  If in doubt, say "N".
-
-menu "DRM i915 Debugging"
-
-depends on DRM_I915
-
-source drivers/gpu/drm/i915/Kconfig.debug
-
-endmenu

drivers/gpu/drm/i915/Kconfig.debug

-config DRM_I915_WERROR
-	bool "Force GCC to throw an error instead of a warning when compiling"
-	default n
-	---help---
-	  Add -Werror to the build flags for (and only for) i915.ko

drivers/gpu/drm/i915/Makefile

@@ -2,8 +2,6 @@
 # Makefile for the drm device driver.  This driver provides support for the
 # Direct Rendering Infrastructure (DRI) in XFree86 4.1.0 and higher.
 
-subdir-ccflags-$(CONFIG_DRM_I915_WERROR) := -Werror
-
 # Please keep these build lists sorted!
 
 # core driver code