xen/arm: platform: address violation of MISRA C Rule 7.2

Rule 7.2 states: "A u or U suffix shall be applied to all integer
constants that are represented in an unsigned type".

Some PM_* constants are unsigned quantities, despite some
of them being representable in a signed type, so a 'U' suffix
should be present.

No functional change.

Signed-off-by: Nicola Vetrini <nicola.vetrini@bugseng.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>

xen/arch/arm/platforms/brcm-raspberry-pi.c

@@ -47,11 +47,11 @@ static const struct dt_device_match rpi4_blacklist_dev[] __initconst =
 };
 
 
-#define PM_PASSWORD                 0x5a000000
+#define PM_PASSWORD                 0x5a000000U
 #define PM_RSTC                     0x1c
 #define PM_WDOG                     0x24
-#define PM_RSTC_WRCFG_FULL_RESET    0x00000020
-#define PM_RSTC_WRCFG_CLR           0xffffffcf
+#define PM_RSTC_WRCFG_FULL_RESET    0x00000020U
+#define PM_RSTC_WRCFG_CLR           0xffffffcfU
 
 static void __iomem *rpi4_map_watchdog(void)
 {