arm: bcm283x undefined reference to "print_cpuinfo"

Builds for Raspberry Pi targets fail when CONFIG_DISPLAY_CPUINFO is
enabled and following error can be seen -
common/board_f.o:(.rodata.init_sequence_f+0x90):
    undefined reference to `print_cpuinfo'

Added implementation of function "print_cpuinfo"

Signed-off-by: Naveen Kumar Chaudhary <naveenchaudhary2010@hotmail.com>
diff --git a/arch/arm/mach-bcm283x/init.c b/arch/arm/mach-bcm283x/init.c
index 183650a..7265faf 100644
--- a/arch/arm/mach-bcm283x/init.c
+++ b/arch/arm/mach-bcm283x/init.c
@@ -146,6 +146,14 @@
 	return 0;
 }
 
+#if defined(CONFIG_DISPLAY_CPUINFO)
+int print_cpuinfo(void)
+{
+	printf("CPU: BCM283x\n");
+	return 0;
+}
+#endif
+
 #ifdef CONFIG_ARMV7_LPAE
 #ifdef CONFIG_TARGET_RPI_4_32B
 #define BCM2711_RPI4_PCIE_XHCI_MMIO_VIRT	0xffc00000UL