KVM: Remove useless assignment

Line 1809 of kvm_main.c is useless, value is overwritten in line 1815:

1809         now = min(count, PAGE_SIZE / size);
1810
1811         if (!down)
1812                 in_page = PAGE_SIZE - offset_in_page(address);
1813         else
1814                 in_page = offset_in_page(address) + size;
1815         now = min(count, (unsigned long)in_page / size);
1816         if (!now) {

Signed-off-by: Laurent Vivier <Laurent.Vivier@bull.net>
Signed-off-by: Avi Kivity <avi@qumranet.com>