OMAP4: clocks: Fix ES2 clock issues

Fix a few OMAP4430 clock tree problems after the recent manual merge of the
various ES2 clock patches:

- usim optional clock and its parent had the same name, rename the parent
usim_fclk -> usim_ck

- OPTFCLKEN_CLK32K is not handled anymore by the USBPHYOCP2SCP module in ES2
Create a new clock that belongs to CM_ALWON_USBPHY_CLKCTRL register

This patch depends on some of the PRCM macro updates from Rajendra.

Signed-off-by: Benoit Cousson <b-cousson@ti.com>
[paul@pwsan.com: tweaked patch description]
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Cc: Rajendra Nayak <rnayak@ti.com>