[IA64] Split 16-bit severity field in sal_log_record_header

ERR_SEVERITY item is defined as a 8 bits item in SAL documentation
($B.2.1 rev december 2003), but as an u16 in sal.h.
This has the side effect that current code in mca.c may not call
ia64_sal_clear_state_info() upon receiving corrected platform errors
if there are bits set in the validation byte.  Reported by Xavier Bru.
Signed-off-by: Tony Luck <tony.luck@intel.com>

include/asm-ia64/sal.h

@@ -320,7 +320,8 @@ typedef struct sal_log_timestamp {
 typedef struct sal_log_record_header {
 	u64 id;				/* Unique monotonically increasing ID */
 	sal_log_revision_t revision;	/* Major and Minor revision of header */
-	u16 severity;			/* Error Severity */
+	u8 severity;			/* Error Severity */
+	u8 validation_bits;		/* 0: platform_guid, 1: !timestamp */
 	u32 len;			/* Length of this error log in bytes */
 	sal_log_timestamp_t timestamp;	/* Timestamp */
 	efi_guid_t platform_guid;	/* Unique OEM Platform ID */