drivers/intel/i210/Makefile.inc: Fix "No such file or directory" error

Fix:
cc1: error: src/drivers/intel/i210: No such file or directory [-Werror=missing-include-dirs]

Change-Id: I94b0f99353ed3a582ea590cbc6b12dec6294c75d
Signed-off-by: Elyes Haouas <ehaouas@noos.fr>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/70468
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Eric Lai <eric_lai@quanta.corp-partner.google.com>
diff --git a/src/drivers/intel/i210/Makefile.inc b/src/drivers/intel/i210/Makefile.inc
index 218b1b4..bbbde88 100644
--- a/src/drivers/intel/i210/Makefile.inc
+++ b/src/drivers/intel/i210/Makefile.inc
@@ -3,5 +3,5 @@
 ramstage-$(CONFIG_DRIVER_INTEL_I210)+= i210.c
 
 ifeq ($(CONFIG_DRIVER_INTEL_I210),y)
-CFLAGS_x86_32 += -Isrc/drivers/intel/i210
+CPPFLAGS_common += -I$(src)/drivers/intel/i210/include
 endif
diff --git a/src/drivers/intel/i210/i210.h b/src/drivers/intel/i210/include/i210.h
similarity index 100%
rename from src/drivers/intel/i210/i210.h
rename to src/drivers/intel/i210/include/i210.h