crda: Fix the linking order to avoid compilation error

While linking the crda.o and libreg.so, first put crda.o
and then -lreg. This fixed the below error:

  GEN  keys-gcrypt.c
  Trusted pubkeys: pubkeys/linville.key.pub.pem
  CC   libreg.so
  CC   crda.o
  LD   crda
crda.o: In function `main':
crda/crda.c:196: undefined reference to `reglib_get_rd_alpha2'
collect2: ld returned 1 exit status
make: *** [crda] Error 1

Note: This still doesn't fix the below error (will send another mail)

  CHK  /usr/lib/crda/regulatory.bin
Database signature verification failed.
Invalid or empty regulatory file, note: a binary regulatory file should be used.
make: *** [verify] Error 234

Signed-off-by: Luis R. Rodriguez <mcgrof@do-not-panic.com>
Signed-off-by: Chaitanya T K <chaitanya.mgit@gmail.com>
crda: Add DESTDIR support in install-libreg* rules in Makefile

Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: Luis R. Rodriguez <mcgrof@do-not-panic.com>