stm32mp1: cosmetic: remove unnecessary include

Remove post.h include as it is used in spl.c

Signed-off-by: Patrick Delaunay <patrick.delaunay@st.com>
diff --git a/board/st/stm32mp1/spl.c b/board/st/stm32mp1/spl.c
index a7844f2..e19be0f 100644
--- a/board/st/stm32mp1/spl.c
+++ b/board/st/stm32mp1/spl.c
@@ -9,7 +9,6 @@
 #include <dm.h>
 #include <ram.h>
 #include <asm/io.h>
-#include <post.h>
 #include <power/pmic.h>
 #include <power/stpmic1.h>
 #include <asm/arch/ddr.h>