[SMBIOS] Interpret UUIDs as being in network-endian order

Various specification documents disagree about the byte ordering of
UUIDs.  However, SMBIOS seems to use the standard in which everything is
in network-endian order.

This doesn't affect anything sent on the wire; only what gets printed on
the screen when the "uuid" variable is displayed.

src/core/uuid.c

 	static char buf[37]; /* "00000000-0000-0000-0000-000000000000" */
 
 	sprintf ( buf, "%08lx-%04x-%04x-%04x-%02x%02x%02x%02x%02x%02x",
-		  le32_to_cpu ( uuid->canonical.a ),
-		  le16_to_cpu ( uuid->canonical.b ),
-		  le16_to_cpu ( uuid->canonical.c ),
+		  be32_to_cpu ( uuid->canonical.a ),
+		  be16_to_cpu ( uuid->canonical.b ),
+		  be16_to_cpu ( uuid->canonical.c ),
 		  be16_to_cpu ( uuid->canonical.d ),
 		  uuid->canonical.e[0], uuid->canonical.e[1],
 		  uuid->canonical.e[2], uuid->canonical.e[3],

src/include/gpxe/uuid.h

 union uuid {
 	/** Canonical form (00000000-0000-0000-0000-000000000000) */
 	struct {
-		/** 8 hex digits, little-endian */
+		/** 8 hex digits, big-endian */
 		uint32_t a;
-		/** 2 hex digits, little-endian */
+		/** 2 hex digits, big-endian */
 		uint16_t b;
-		/** 2 hex digits, little-endian */
+		/** 2 hex digits, big-endian */
 		uint16_t c;
 		/** 2 hex digits, big-endian */
 		uint16_t d;