ARM: zynq: Do not print message about boot device

This information is shown already that's why there is no reason to print it
again via custom prints.

U-Boot SPL 2020.01-03080-ga6214d033bd0 (Mar 05 2020 - 09:59:05 +0100)
mmc boot
Trying to boot from MMC1

or

U-Boot SPL 2020.01-03080-ga6214d033bd0 (Mar 05 2020 - 10:49:46 +0100)
qspi boot
Trying to boot from SPI

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
diff --git a/arch/arm/mach-zynq/spl.c b/arch/arm/mach-zynq/spl.c
index e89e46c..02a7dc9 100644
--- a/arch/arm/mach-zynq/spl.c
+++ b/arch/arm/mach-zynq/spl.c
@@ -45,7 +45,6 @@
 	switch ((zynq_slcr_get_boot_mode()) & ZYNQ_BM_MASK) {
 #ifdef CONFIG_SPL_SPI_SUPPORT
 	case ZYNQ_BM_QSPI:
-		puts("qspi boot\n");
 		mode = BOOT_DEVICE_SPI;
 		break;
 #endif
@@ -57,7 +56,6 @@
 		break;
 #ifdef CONFIG_SPL_MMC_SUPPORT
 	case ZYNQ_BM_SD:
-		puts("mmc boot\n");
 		mode = BOOT_DEVICE_MMC1;
 		break;
 #endif