clk: ti: Fix FAPLL recalc_rate for rounding errors

We need to round the calculated value to have it match the requested rate.

While at it, let's fix a typo and use a define for SYNTH_MAX_DIV_M as we
will need it in later patches for set_rate.

And let's remove two unused includes.

Cc: Brian Hutchinson <b.hutchman@gmail.com>
Cc: Matthijs van Duin <matthijsvanduin@gmail.com>
Cc: Tero Kristo <t-kristo@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Tero Kristo <t-kristo@ti.com>