Unlike PVR_POWER8, etc ...., PVR_7450 represents a full PVR
value and not a family value.

To avoid confusion, do like E500 family and define the relevant
PVR_VER_xxxx values for the 7450 family:
  0x8000 ==> 7450
  0x8001 ==> 7455
  0x8002 ==> 7447
  0x8003 ==> 7447A
  0x8004 ==> 7448

And use them to detect 7450 family for perf events.
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <error27@gmail.com>
Link: https://lore.kernel.org/r/202302260657.7dM9Uwev-lkp@intel.com/
Fixes: ec3eb9d9 ("powerpc/perf: Use PVR rather than oprofile field to determine CPU version")
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/99ca1da2e5a6cf82a8abf4bc034918e500e31781.1677513277.git.christophe.leroy@csgroup.eu