OMAP2/3: clock: fix fint calculation for DPLL_FREQSEL

OMAP2/3: clock: fix fint calculation for DPLL_FREQSEL

In OMAP35X TRM Rev 2010-05 Figure 7-18 "DPLL With EMI Reduction
Feature", it is shown that the internal frequency is calculated by
CLK_IN/(N+1). However, the value passed to _dpll_test_fint() is
already "N+1" since Linux is using the values to divide by. In the
technical reference manual, "N" is referring to the divider's register
value (0-127).

During power management testing, it was observed that programming the
wrong jitter correction value can cause the system to become unstable
and eventually crash.

Signed-off-by: John Ogness <john.ogness@linutronix.de>
[paul@pwsan.com: added second paragraph to commit message]
Signed-off-by: Paul Walmsley <paul@pwsan.com>