i915: use different CFLAGS/LIBS variables than i965/anv

Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Emil Velikov <emil.velikov@collabora.com>
diff --git a/configure.ac b/configure.ac
index 9de1b42..ce9e4ff 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1830,7 +1830,7 @@
         xi915)
             require_libdrm "i915"
             HAVE_I915_DRI=yes
-            PKG_CHECK_MODULES([INTEL], [libdrm >= $LIBDRM_INTEL_REQUIRED libdrm_intel >= $LIBDRM_INTEL_REQUIRED])
+            PKG_CHECK_MODULES([I915], [libdrm >= $LIBDRM_INTEL_REQUIRED libdrm_intel >= $LIBDRM_INTEL_REQUIRED])
             ;;
         xi965)
             require_libdrm "i965"
@@ -2418,7 +2418,7 @@
             ;;
         xi915)
             HAVE_GALLIUM_I915=yes
-            PKG_CHECK_MODULES([INTEL], [libdrm >= $LIBDRM_INTEL_REQUIRED libdrm_intel >= $LIBDRM_INTEL_REQUIRED])
+            PKG_CHECK_MODULES([I915], [libdrm >= $LIBDRM_INTEL_REQUIRED libdrm_intel >= $LIBDRM_INTEL_REQUIRED])
             require_libdrm "Gallium i915"
             ;;
         xr300)