ia32: Merge the attributes use_frame, need_stackent, need_32bit_stackent and need_64bit_stackent into one attribute.

* Out of the 16 possible combinations of these four boolean attributes, only four are sensible.
* This correct the latent bug, that not all of these attributes were compared in ia32_attrs_equal_().
ia32: Cleanup in create_fpu_mode_reload() and create_fpu_mode_spill().
ia32: Cleanup in peephole_ia32_Lea().
ia32: Correct and simplify sim_Keep().

It only worked, if a single value, which was at TOS, should be popped.
ia32: Pass the source/target mode to the constructors of Conv_{I2FP,FP2FP,FP2I}.
ia32: Pass the store mode to the constructor of Push.
ia32: Generate the input enum for Call.
ia32: Cleanup in gen_Call().
ia32: Do not shadow variables, which even contain the same values.
ia32: Correct AM specification of Bsf, Bsr and Popcnt.
be: Make be_duplicate_deps() static.
ir: Use add_irn_deps().
ia32: Remove stale case in gen_shift_binop().

l_{Shl,Shr,Sar}Dep are long gone.
So there are no shift operations with a third input (dependency) anymore.
ia32: Update code to the removal of the symconst sign.
ia32: Unify creation of Immediates.

* Provide a function for a full Immediate (entity + constant) and one for just a constant
* Place all immediates in the start block
* This slightly reduces the inconsistency, that some constant-only Immediates had no_pic_adjust set
ia32: Cleanup in fix_pic_addresses().

* Use enum instead of magic number
* Do not unnecessarily lose debug information
tv: Simplify implementation of tarval_abs().
ia32: Slightly simplify the gcc PIC special case in x86_cpuid().
be: Make be_set_constr_in() static.