rust: Add powerpc64 as a 64-bit target_arch in c_types.rs

powerpc kernel code uses int-ll64.h.

Signed-off-by: Michael Ellerman <[email protected]>

Author: mpe

rust/kernel/c_types.rs

@@ -60,7 +60,11 @@ mod c {
     pub type c_size_t = usize;
 }
 
-#[cfg(any(target_arch = "aarch64", target_arch = "x86_64"))]
+#[cfg(any(
+    target_arch = "aarch64",
+    target_arch = "x86_64",
+    target_arch = "powerpc64"
+))]
 mod c {
     /// C `void` type.
     pub type c_void = core::ffi::c_void;