zynqmp_sdcard: use -O2 instead of -Os

-Os causes SHA3-384 hash mismatch at runtime on AArch64 Cortex-A53
with ARM crypto extensions (WOLFSSL_ARMASM). -O0 and -O2 both work
correctly. Append CFLAGS_EXTRA+=-O2 to override the Makefile's
default -Os when DEBUG=0.

Author: dgarske

config/examples/zynqmp_sdcard.config

@@ -23,6 +23,10 @@ DEBUG_SYMBOLS=1
 DEBUG_UART=1
 CFLAGS_EXTRA+=-DDEBUG_ZYNQ=1
 
+# Use -O2 instead of -Os (the default when DEBUG=0). -Os causes SHA3-384
+# hash mismatch at runtime on AArch64 Cortex-A53 with ARM crypto extensions.
+CFLAGS_EXTRA+=-O2
+
 # SD card support - use SDHCI driver
 DISK_SDCARD?=1
 DISK_EMMC?=0