refactor(st): move macros to common folder

As these definitions will be the same for STM32MP1 and STM32MP2, move
PLATFORM_MTD_MAX_PAGE_SIZE and DWL_BUFFER_SIZE macro definition to the
file: plat/st/common/include/stm32mp_common.h

Signed-off-by: Yann Gautier <yann.gautier@st.com>
Change-Id: I480669d009d15fec753298f47b136e34fa240132
diff --git a/plat/st/common/include/stm32mp_common.h b/plat/st/common/include/stm32mp_common.h
index 66b9310..0ff6092 100644
--- a/plat/st/common/include/stm32mp_common.h
+++ b/plat/st/common/include/stm32mp_common.h
@@ -20,6 +20,12 @@
 /* FWU configuration (max supported value is 15) */
 #define FWU_MAX_TRIAL_REBOOT		U(3)
 
+/* Define maximum page size for NAND devices */
+#define PLATFORM_MTD_MAX_PAGE_SIZE	U(0x1000)
+
+/* Needed by STM32CubeProgrammer support */
+#define DWL_BUFFER_SIZE			U(0x01000000)
+
 /* Functions to save and get boot context address given by ROM code */
 void stm32mp_save_boot_ctx_address(uintptr_t address);
 uintptr_t stm32mp_get_boot_ctx_address(void);