arm64: zynqmp: Propagate error value from psu_init()

psu_init() returns int which wasn't declared and checked.
The patch is fixing function declarations and code to handle return
values properly.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>

arch/arm/cpu/armv8/zynqmp/spl.c

@@ -129,12 +129,13 @@ u32 spl_boot_mode(const u32 boot_device)
 	}
 }
 
-__weak void psu_init(void)
+__weak int psu_init(void)
 {
 	/*
 	 * This function is overridden by the one in
 	 * board/xilinx/zynqmp/(platform)/psu_init_gpl.c, if it exists.
 	 */
+	return -1;
 }
 
 #ifdef CONFIG_SPL_OS_BOOT

arch/arm/include/asm/arch-zynqmp/sys_proto.h

@@ -33,7 +33,7 @@ enum {
 int zynq_board_read_rom_ethaddr(unsigned char *ethaddr);
 unsigned int zynqmp_get_silicon_version(void);
 
-void psu_init(void);
+int psu_init(void);
 
 void handoff_setup(void);
 

board/xilinx/zynqmp/zynqmp.c

@@ -237,15 +237,16 @@ static char *zynqmp_get_silicon_idcode_name(void)
 
 int board_early_init_f(void)
 {
+	int ret = 0;
 #if !defined(CONFIG_SPL_BUILD) && defined(CONFIG_CLK_ZYNQMP)
 	zynqmp_pmufw_version();
 #endif
 
 #if defined(CONFIG_SPL_BUILD) || defined(CONFIG_ZYNQMP_PSU_INIT_ENABLED)
-	psu_init();
+	ret = psu_init();
 #endif
 
-	return 0;
+	return ret;
 }
 
 #define ZYNQMP_VERSION_SIZE	9