riscv: sifive/fu540: Drop NET_RANDOM_ETHADDR

This option was enabled during the earlier U-Boot porting time. Now
we already have the OTP driver in place and the unique MAC address
is read from the OTP, there is no need to turn on this option.

Signed-off-by: Bin Meng <bin.meng@windriver.com>
Reviewed-by: Leo Liang <ycliang@andestech.com>
Reviewed-by: Rick Chen <rick@andestech.com>
Reviewed-by: Pragnesh Patel <pragnesh.patel@sifive.com>
Tested-by: Pragnesh Patel <pragnesh.patel@sifive.com>
diff --git a/board/sifive/fu540/Kconfig b/board/sifive/fu540/Kconfig
index fc28120..e70d1e5 100644
--- a/board/sifive/fu540/Kconfig
+++ b/board/sifive/fu540/Kconfig
@@ -41,7 +41,6 @@
 	imply EFI_PARTITION
 	imply IP_DYN
 	imply ISO_PARTITION
-	imply NET_RANDOM_ETHADDR
 	imply PHY_LIB
 	imply PHY_MSCC
 	imply SPI_FLASH