drm/xe: drop redundant W=1 warnings from Makefile

Since commit a61ddb43 ("drm: enable (most) W=1 warnings by default
across the subsystem"), most of the extra warnings in the driver
Makefile are redundant. Remove them.

Note that -Wmissing-declarations and -Wmissing-prototypes are always
enabled by default in scripts/Makefile.extrawarn.
Acked-by: Lucas De Marchi <lucas.demarchi@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/958a67adcbb64d3a387d2a07d83b05d71176e938.1716471145.git.jani.nikula@intel.com

drivers/gpu/drm/xe/Makefile

@@ -3,31 +3,8 @@
 # Makefile for the drm device driver.  This driver provides support for the
 # Direct Rendering Infrastructure (DRI) in XFree86 4.1.0 and higher.
 
-# Unconditionally enable W=1 warnings locally
-# --- begin copy-paste W=1 warnings from scripts/Makefile.extrawarn
-subdir-ccflags-y += -Wextra -Wunused -Wno-unused-parameter
-subdir-ccflags-y += -Wmissing-declarations
-subdir-ccflags-y += $(call cc-option, -Wrestrict)
-subdir-ccflags-y += -Wmissing-format-attribute
-subdir-ccflags-y += -Wmissing-prototypes
-subdir-ccflags-y += -Wold-style-definition
-subdir-ccflags-y += -Wmissing-include-dirs
-subdir-ccflags-y += $(call cc-option, -Wunused-but-set-variable)
-subdir-ccflags-y += $(call cc-option, -Wunused-const-variable)
-subdir-ccflags-y += $(call cc-option, -Wpacked-not-aligned)
-subdir-ccflags-y += $(call cc-option, -Wformat-overflow)
+# Enable W=1 warnings not enabled in drm subsystem Makefile
 subdir-ccflags-y += $(call cc-option, -Wformat-truncation)
-subdir-ccflags-y += $(call cc-option, -Wstringop-truncation)
-# The following turn off the warnings enabled by -Wextra
-ifeq ($(findstring 2, $(KBUILD_EXTRA_WARN)),)
-subdir-ccflags-y += -Wno-missing-field-initializers
-subdir-ccflags-y += -Wno-type-limits
-subdir-ccflags-y += -Wno-shift-negative-value
-endif
-ifeq ($(findstring 3, $(KBUILD_EXTRA_WARN)),)
-subdir-ccflags-y += -Wno-sign-compare
-endif
-# --- end copy-paste
 
 # Enable -Werror in CI and development
 subdir-ccflags-$(CONFIG_DRM_XE_WERROR) += -Werror