Overview
 - distinguish between PLL1- and PLL2-derived SYSCLKs
 - PLL-derived AUX ans bypass clocks are sourced
   before the multiplier and divider(s)
 - add CLK_PSC flag (set at init for clks with 'lpsc' filled out)
 - blindly dropped the remaining boot-time PSC inits
 - more lowercase clock names, and removal of '_clk' suffix in strings

and from Dave:
 - Add PSC_DSP flag for updating dm644x DSP and VICP clocks
 - When disabling unused clocks, avoid WARN() spewage
 - On dm355, list two more clocks
 - On dm64xx, list the DSP clocks too
 - Correct some LPSC definitions:  remove invalid, define dm646x ARM
 - AEMIF shouldn't be "always enabled" on dm6446 (EVM may need NOR tweaks)

Notes:
 - PWM[0,1] on dm6467 hang the system when disabled.  Add the
   'usecount = 1' workaround and 'REVISIT' comment.

TODO:
- move the device-specific PSC init into <device>.c

This was boot-tested on dm6446, dm355, dm6467 with a quick
sanity check of /proc/davinci_clocks.
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>