soc/amd/picasso/psp_verstage/Makefile.inc: Remove path to non-existent directories

Found using 'Wmissing-include-dirs' command option.
Fix:
cc1: error: ../../src/soc/amd/picasso/psp_verstage/include: No such file or directory [-Werror=missing-include-dirs]

Change-Id: I7713eef54686c58a83215c461c3274cec89e32b0
Signed-off-by: Elyes Haouas <ehaouas@noos.fr>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/71587
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Fred Reitberger <reitbergerfred@gmail.com>
diff --git a/src/soc/amd/picasso/psp_verstage/Makefile.inc b/src/soc/amd/picasso/psp_verstage/Makefile.inc
index 82d8efa..bf1a694 100644
--- a/src/soc/amd/picasso/psp_verstage/Makefile.inc
+++ b/src/soc/amd/picasso/psp_verstage/Makefile.inc
@@ -1,6 +1,5 @@
 # SPDX-License-Identifier: GPL-2.0-only
 
-verstage-generic-ccopts += -I$(src)/soc/amd/picasso/psp_verstage/include
 verstage-generic-ccopts += -I$(src)/vendorcode/amd/fsp/picasso/include
 
 verstage-y += svc.c