common/cmd_flash.c: Fix GCC 4.6 build warnings

common/cmd_flash.c: Fix GCC 4.6 build warnings

Fix:
cmd_flash.c:355:32: warning: 'info' may be used uninitialized in this
function [-Wuninitialized]
cmd_flash.c:354:10: warning: 'sect_first' may be used uninitialized in
this function [-Wuninitialized]
cmd_flash.c:354:10: warning: 'sect_last' may be used uninitialized in
this function [-Wuninitialized]
cmd_flash.c: In function 'do_protect':
cmd_flash.c:540:9: warning: 'info' may be used uninitialized in this
function [-Wuninitialized]
cmd_flash.c:538:9: warning: 'sect_first' may be used uninitialized in
this function [-Wuninitialized]
cmd_flash.c:538:9: warning: 'sect_last' may be used uninitialized in
this function [-Wuninitialized]

Signed-off-by: Wolfgang Denk <wd@denx.de>