[cmdline] Make "reboot" command available by default

Requested-by: Sven Dreyer <sven@dreyer-net.de>
Signed-off-by: Michael Brown <mcb30@ipxe.org>

src/config/defaults/pcbios.h

 #define	SANBOOT_PROTO_IB_SRP	/* Infiniband SCSI RDMA protocol */
 #define	SANBOOT_PROTO_FCP	/* Fibre Channel protocol */
 
+#define	REBOOT_CMD		/* Reboot command */
+
 #endif /* CONFIG_DEFAULTS_PCBIOS_H */

src/config/general.h

 #define DHCP_CMD		/* DHCP management commands */
 #define SANBOOT_CMD		/* SAN boot commands */
 #define LOGIN_CMD		/* Login command */
-#undef	TIME_CMD		/* Time commands */
-#undef	DIGEST_CMD		/* Image crypto digest commands */
-#undef	LOTEST_CMD		/* Loopback testing commands */
-#undef	VLAN_CMD		/* VLAN commands */
-#undef	PXE_CMD			/* PXE commands */
-#undef	REBOOT_CMD		/* Reboot command */
+//#define TIME_CMD		/* Time commands */
+//#define DIGEST_CMD		/* Image crypto digest commands */
+//#define LOTEST_CMD		/* Loopback testing commands */
+//#define VLAN_CMD		/* VLAN commands */
+//#define PXE_CMD		/* PXE commands */
+//#define REBOOT_CMD		/* Reboot command */
 
 /*
  * ROM-specific options