stage2: Add SPARC function alignment

This is based on @kubkon's suggestion.

src/target.zig

@@ -669,6 +669,7 @@ pub fn defaultFunctionAlignment(target: std.Target) u32 {
     return switch (target.cpu.arch) {
         .arm, .armeb => 4,
         .aarch64, .aarch64_32, .aarch64_be => 4,
+        .sparc, .sparcel, .sparcv9 => 4,
         .riscv64 => 2,
         else => 1,
     };