make: Remove duplicate occurence of driverfuncs.c

driverfuncs.o is already contained in libmesa.a, so remove it from the
following source lists:
    src/mesa/drivers/dri/Makefiles.defines:COMMON_SOURCES.
    src/mesa/drivers/dri/swrast/Makefile:SWRAST_COMMON_SOURCES

Reviewed-by: Ian Romanick <idr@freedesktop.org>
Signed-off-by: Chad Versace <chad@chad-versace.us>

src/mesa/drivers/dri/Makefile.defines

@@ -7,7 +7,6 @@ COMMON_GALLIUM_SOURCES = \
         ../common/xmlconfig.c
 
 COMMON_SOURCES = $(COMMON_GALLIUM_SOURCES) \
-        ../../common/driverfuncs.c \
         ../common/texmem.c \
         ../common/drirenderbuffer.c
 

src/mesa/drivers/dri/swrast/Makefile

@@ -20,7 +20,6 @@ C_SOURCES = \
 ASM_SOURCES =
 
 SWRAST_COMMON_SOURCES = \
-	../../common/driverfuncs.c \
 	../common/utils.c \
 	../common/drisw_util.c