nb/intel/ironlake/raminit_heci.c: Turn into compilation unit

Remove the temporary `raminit_heci.c` include and make it a proper
compilation unit. Export the `setup_heci_uma()` function.

Change-Id: Ia6782a0cb5e731d58764d0fa4ee256bfc8cef98a
Signed-off-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/61929
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
diff --git a/src/northbridge/intel/ironlake/raminit.h b/src/northbridge/intel/ironlake/raminit.h
index edfce51..05e5ac3 100644
--- a/src/northbridge/intel/ironlake/raminit.h
+++ b/src/northbridge/intel/ironlake/raminit.h
@@ -106,4 +106,6 @@
 void early_quickpath_init(struct raminfo *info, const u8 x2ca8);
 void late_quickpath_init(struct raminfo *info, const int s3resume);
 
+void setup_heci_uma(struct raminfo *info);
+
 #endif				/* RAMINIT_H */