configs: sandbox: enable PCAP capture cmd

Enable CONFIG_CMD_PCAP for testing PCAP capture.

Signed-off-by: Ramon Fried <rfried.dev@gmail.com>
Acked-by: Joe Hershberger <joe.hershberger@ni.com>
diff --git a/configs/sandbox_defconfig b/configs/sandbox_defconfig
index 7355e3a..968ffda 100644
--- a/configs/sandbox_defconfig
+++ b/configs/sandbox_defconfig
@@ -49,6 +49,7 @@
 CONFIG_CMD_USB=y
 CONFIG_CMD_AXI=y
 CONFIG_CMD_AB_SELECT=y
+CONFIG_CMD_PCAP=y
 CONFIG_CMD_TFTPPUT=y
 CONFIG_CMD_TFTPSRV=y
 CONFIG_CMD_RARP=y