std.c: Fix MAP for serenity

I accidentally translated MAP_ constants representing the type as
individual fields. MAP_FILE is for compatibility only and not needed
here.

Author: linusg

lib/std/c.zig

@@ -8760,18 +8760,18 @@ pub const MAP = switch (native_os) {
     },
     // https://github.com/SerenityOS/serenity/blob/6d59d4d3d9e76e39112842ec487840828f1c9bfe/Kernel/API/POSIX/sys/mman.h#L16-L26
     .serenity => packed struct(c_int) {
-        FILE: bool = false,
-        SHARED: bool = false,
-        PRIVATE: bool = false,
-        _3: u2 = 0,
+        TYPE: enum(u4) {
+            SHARED = 0x01,
+            PRIVATE = 0x02,
+        },
         FIXED: bool = false,
         ANONYMOUS: bool = false,
         STACK: bool = false,
         NORESERVE: bool = false,
         RANDOMIZED: bool = false,
         PURGEABLE: bool = false,
         FIXED_NOREPLACE: bool = false,
-        _: std.meta.Int(.unsigned, @bitSizeOf(c_int) - 12) = 0,
+        _: std.meta.Int(.unsigned, @bitSizeOf(c_int) - 11) = 0,
     },
     else => void,
 };