x86/tlb: Clean up and unify TLB_FLUSH_ALL definition

Since sizeof(long) is 4 in x86_32 mode, and it's 8 in x86_64
mode, sizeof(long long) is also 8 byte in x86_64 mode.
use long mode can fit TLB_FLUSH_ALL defination here both in 32
or 64 bits mode.

Signed-off-by: Alex Shi <alex.shi@intel.com>
Link: http://lkml.kernel.org/n/tip-evv5bekiipi2pmyzdsy8lkkw@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>