dts: arm: st: h7: combine sram1 and sram2 memory size

Combining the two regions provides enough memory to
successfully build applications.

Note that SRAM1 and SRAM2 are continuous regions.

Signed-off-by: Fabrice DJIATSA <[email protected]>

Author: djiatsaf-st

tests/drivers/memc/ram/boards/stm32h735g_disco.overlay

@@ -0,0 +1,7 @@
+/delete-node/ &sram2;
+
+/* D2 domain, AHB SRAM */
+&sram1{
+	reg = <0x30000000 DT_SIZE_K(32)>;
+	zephyr,memory-region = "SRAM1-2";
+};