std: fix long double size for loongarch.

Author: yxd-ym

lib/std/Target.zig

@@ -2089,6 +2089,8 @@ pub fn c_type_bit_size(target: Target, c_type: CType) u16 {
                     .sparcel,
                     .wasm32,
                     .wasm64,
+                    .loongarch32,
+                    .loongarch64,
                     => return 128,
 
                     else => return 64,
@@ -2194,6 +2196,8 @@ pub fn c_type_bit_size(target: Target, c_type: CType) u16 {
                     .sparcel,
                     .wasm32,
                     .wasm64,
+                    .loongarch32,
+                    .loongarch64,
                     => return 128,
 
                     else => return 64,