Fix ppu_register_function_at with unaligned parameters (#17718)

This fixes some crashes in interpreter mode when calling functions like
`sys_dbg_write_process_memory` to write data which may not be an
instruction.

---------

Co-authored-by: Elad <18193363+elad335@users.noreply.github.com>

rpcs3/Emu/Cell/PPUThread.cpp

@@ -827,6 +827,9 @@ extern void ppu_register_function_at(u32 addr, u32 size, ppu_intrp_func_t ptr =
 		return;
 	}
 
+	size = utils::align<u32>(size + addr % 4, 4);
+	addr &= -4;
+
 	if (g_cfg.core.ppu_decoder == ppu_decoder_type::llvm)
 	{
 		return;