Fix two pointer-to-int-cast warnings when compiling for the 32-bit parisc
platform:

kernel/kexec_file.c: In function ‘crash_prepare_elf64_headers’:
kernel/kexec_file.c:1307:19: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
  phdr->p_vaddr = (Elf64_Addr)_text;
                  ^
kernel/kexec_file.c:1324:19: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
  phdr->p_vaddr = (unsigned long long) __va(mstart);
                  ^

Signed-off-by: Helge Deller <deller@gmx.de>