samples: code_relocation_nocopy: update macro for flash size and address

In case of the st,stm32-ospi-nor compatible
new property and node definitions will requires new macro
to get the external NOR flash base address and size

Signed-off-by: Francois Ramu <francois.ramu@st.com>

Author: FRASTM

samples/application_development/code_relocation_nocopy/linker_arm_nocopy.ld

@@ -30,8 +30,8 @@
 /* On stm32 OSPI, external flash is mapped in XIP region at address given by the reg property. */
 
 #define EXTFLASH_NODE	DT_INST(0, st_stm32_ospi_nor)
-#define EXTFLASH_ADDR	DT_REG_ADDR(DT_INST(0, st_stm32_ospi_nor))
-#define EXTFLASH_SIZE	DT_REG_SIZE(DT_INST(0, st_stm32_ospi_nor))
+#define EXTFLASH_ADDR	DT_REG_ADDR_BY_IDX(DT_PARENT(EXTFLASH_NODE), 1)
+#define EXTFLASH_SIZE	(DT_PROP(EXTFLASH_NODE, size) / 8)
 
 #elif defined(CONFIG_STM32_MEMMAP) && DT_NODE_EXISTS(DT_INST(0, st_stm32_qspi_nor))
 /* On stm32 QSPI, external flash is mapped in XIP region at address given by the reg property. */