soc/amd/mendocino/chipset_rembrandt: use right chipset folder

Since the path after the chip keyword needs to point to the directory
that contains the chipset's chip.h file, change this from
soc/amd/rembrandt to soc/amd/mendocino.

Signed-off-by: Felix Held <felix-coreboot@felixheld.de>
Change-Id: I63334fbd59e74df491035b5cf7e296818cc02665
Reviewed-on: https://review.coreboot.org/c/coreboot/+/66688
Reviewed-by: ritul guru <ritul.bits@gmail.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Raul Rangel <rrangel@chromium.org>

src/soc/amd/mendocino/chipset_rembrandt.cb

@@ -1,4 +1,4 @@
-chip soc/amd/rembrandt
+chip soc/amd/mendocino
 	device cpu_cluster 0 on
 	end
 	device domain 0 on