agp: fix shadowed variable warning in amd-k7-agp.c

Introduced between 2.6.25-rc2 and -rc3
drivers/char/agp/amd-k7-agp.c:439:6: warning: symbol 'cap_ptr' shadows an
earlier one
drivers/char/agp/amd-k7-agp.c:414:5: originally declared here

cap_ptr is never used again in this function, don't bother redeclaring.

Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dave Airlie <airlied@linux.ie>