defconfig: at91-sama5d2_ptc_ek: remove unused SYS_EXTRA_OPTIONS

Remove SYS_USE_NANDFLASH, SYS_USE_MMC as they are deprecated and
unused.
The board configurations already use CONFIG_SD_BOOT and
CONFIG_NAND_BOOT respectively.

Signed-off-by: Ludovic Desroches <ludovic.desroches@microchip.com>
[eugen.hristev@microchip.com: rework on latest u-boot]
Signed-off-by: Eugen Hristev <eugen.hristev@microchip.com>
diff --git a/configs/sama5d2_ptc_ek_mmc_defconfig b/configs/sama5d2_ptc_ek_mmc_defconfig
index 7a52c10..9c3c578 100644
--- a/configs/sama5d2_ptc_ek_mmc_defconfig
+++ b/configs/sama5d2_ptc_ek_mmc_defconfig
@@ -7,7 +7,7 @@
 CONFIG_DEBUG_UART=y
 CONFIG_ENV_VARS_UBOOT_CONFIG=y
 CONFIG_FIT=y
-CONFIG_SYS_EXTRA_OPTIONS="SAMA5D2,SYS_USE_MMC"
+CONFIG_SYS_EXTRA_OPTIONS="SAMA5D2"
 CONFIG_SD_BOOT=y
 CONFIG_BOOTDELAY=3
 CONFIG_CONSOLE_MUX=y