fdt: Add -q option to fdt addr for distro_bootcmd

distro_bootcmd uses this construct a few times to test $fdt_addr_r,
and fall back on $fdtcontroladdr if not set/invalid:

    if fdt addr ${fdt_addr_r}; then
        ...
    else
        ...
    fi

If the `fdt addr` test fails, it prints the following  message on the
console, suggesting there is an error when there is not:

    libfdt fdt_check_header(): FDT_ERR_BADMAGIC

To remove this potentially confusing error message, this patch adds -q
as a 'quiet' option for fdt addr, and uses this flag in
config_distro_bootcmd.h

Signed-off-by: Peter Hoyes <Peter.Hoyes@arm.com>
diff --git a/include/config_distro_bootcmd.h b/include/config_distro_bootcmd.h
index 2f90929..c5502388 100644
--- a/include/config_distro_bootcmd.h
+++ b/include/config_distro_bootcmd.h
@@ -126,7 +126,7 @@
 #ifdef CONFIG_CMD_BOOTEFI_BOOTMGR
 #define BOOTENV_EFI_BOOTMGR                                               \
 	"boot_efi_bootmgr="                                               \
-		"if fdt addr ${fdt_addr_r}; then "                        \
+		"if fdt addr -q ${fdt_addr_r}; then "                     \
 			"bootefi bootmgr ${fdt_addr_r};"                  \
 		"else "                                                   \
 			"bootefi bootmgr;"                                \
@@ -141,7 +141,7 @@
 	"boot_efi_binary="                                                \
 		"load ${devtype} ${devnum}:${distro_bootpart} "           \
 			"${kernel_addr_r} efi/boot/"BOOTEFI_NAME"; "      \
-		"if fdt addr ${fdt_addr_r}; then "                        \
+		"if fdt addr -q ${fdt_addr_r}; then "                     \
 			"bootefi ${kernel_addr_r} ${fdt_addr_r};"         \
 		"else "                                                   \
 			"bootefi ${kernel_addr_r} ${fdtcontroladdr};"     \
@@ -360,7 +360,7 @@
 	"setenv bootp_arch " BOOTENV_EFI_PXE_ARCH ";"                     \
 	"if dhcp ${kernel_addr_r}; then "                                 \
 		"tftpboot ${fdt_addr_r} dtb/${efi_fdtfile};"              \
-		"if fdt addr ${fdt_addr_r}; then "                        \
+		"if fdt addr -q ${fdt_addr_r}; then "                     \
 			"bootefi ${kernel_addr_r} ${fdt_addr_r}; "        \
 		"else "                                                   \
 			"bootefi ${kernel_addr_r} ${fdtcontroladdr};"     \