target/i386: Remove obsolete TODO file

The last real change to this file is from 2012, so it is very likely
that this file is completely out-of-date and ignored today. Let's
simply remove it to avoid confusion if someone finds it by accident.

Backports commit 3575b0aea983ad57804c9af739ed8ff7bc168393 from qemu

qemu/target/i386/TODO

@@ -1,31 +0,0 @@
-Correctness issues:
-
-- some eflags manipulation incorrectly reset the bit 0x2.
-- SVM: test, cpu save/restore, SMM save/restore. 
-- x86_64: lcall/ljmp intel/amd differences ?
-- better code fetch (different exception handling + CS.limit support)
-- user/kernel PUSHL/POPL in helper.c
-- add missing cpuid tests
-- return UD exception if LOCK prefix incorrectly used
-- test ldt limit < 7 ?
-- fix some 16 bit sp push/pop overflow (pusha/popa, lcall lret)
-- full support of segment limit/rights 
-- full x87 exception support
-- improve x87 bit exactness (use bochs code ?)
-- DRx register support
-- CR0.AC emulation
-- SSE alignment checks
-
-Optimizations/Features:
-
-- add SVM nested paging support
-- add VMX support
-- add AVX support
-- add SSE5 support
-- fxsave/fxrstor AMD extensions
-- improve monitor/mwait support
-- faster EFLAGS update: consider SZAP, C, O can be updated separately
-  with a bit field in CC_OP and more state variables.
-- evaluate x87 stack pointer statically
-- find a way to avoid translating several time the same TB if CR0.TS
-  is set or not.