Finally fix the pesky x86-2.6 block2mtd related crash (#1058) When erasing blocks...

Finally fix the pesky x86-2.6 block2mtd related crash (#1058) When erasing blocks, block2mtd checks the block on the physical disk to see if everything's filled with 0xff. When grabbing a page from the page cache, it initializes the limit as <start address> + PAGE_SIZE. Turns out that the pointer to the status page is (unsigned long *), and thus it adds (PAGE_SIZE * 4). This would never have been caught, if it wasn't for the unlikely event that block2mtd catches the *last* page available in the system ram and thus tries to scan 4 memory pages from there. The absolutely trivial fix is to do a double cast (cast to (u8 *), add PAGE_SIZE, then cast to (unsigned long *))

... and there was much rejoicing

SVN-Revision: 6318