std.os.uefi: Fix two padding mistakes in the Time struct

```c
//************************************************
//EFI_TIME
//************************************************
// This represents the current time information
typedef struct {
   UINT16    Year;              // 1900 - 9999
   UINT8     Month;             // 1 - 12
   UINT8     Day;               // 1 - 31
   UINT8     Hour;              // 0 - 23
   UINT8     Minute;            // 0 - 59
   UINT8     Second;            // 0 - 59
   UINT8     Pad1;
   UINT32    Nanosecond;        // 0 - 999,999,999
   INT16     TimeZone;          // —1440 to 1440 or 2047
   UINT8     Daylight;
   UINT8     Pad2;
 }   EFI_TIME;
```

lib/std/os/uefi.zig

@@ -113,22 +113,30 @@ pub const Time = extern struct {
     /// 0 - 59
     second: u8,
 
+    _pad1: u8,
+
     /// 0 - 999999999
     nanosecond: u32,
 
     /// The time's offset in minutes from UTC.
     /// Allowed values are -1440 to 1440 or unspecified_timezone
     timezone: i16,
-    daylight: packed struct {
+    daylight: packed struct(u8) {
-        _pad1: u6,
-
         /// If true, the time has been adjusted for daylight savings time.
         in_daylight: bool,
 
         /// If true, the time is affected by daylight savings time.
         adjust_daylight: bool,
+
+        _: u6,
     },
 
+    _pad2: u8,
+
+    comptime {
+        std.debug.assert(@sizeOf(Time) == 16);
+    }
+
     /// Time is to be interpreted as local time
     pub const unspecified_timezone: i16 = 0x7ff;