ARM: shmobile: rcar-gen2: Use SZ_256K definition

Use SZ_256K instead of calculating the same value.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Link: https://lore.kernel.org/c54097a263eb3e451e5e223609a3630d4409dcdd.1753951039.git.geert+renesas@glider.be

Author: geertu

arch/arm/mach-shmobile/pm-rcar-gen2.c

@@ -81,7 +81,7 @@ void __init rcar_gen2_pm_init(void)
 
 map:
 	/* RAM for jump stub, because BAR requires 256KB aligned address */
-	if (res.start & (256 * 1024 - 1) ||
+	if (res.start & (SZ_256K - 1) ||
 	    resource_size(&res) < shmobile_boot_size) {
 		pr_err("Invalid smp-sram region\n");
 		return;