ARM: OMAP2+: hwmod: get rid of all omap_clk_get_by_name usage

ARM: OMAP2+: hwmod: get rid of all omap_clk_get_by_name usage

Moving to Common clk framework for OMAP would mean we no longer use
internal lookup mechanism like omap_clk_get_by_name().
get rid of all its usage mostly from hwmod and omap_device
code.

Moving to clk_get() also means the respective platforms
need the clkdev tables updated with an entry for all clocks
used by hwmod to have clock name same as the alias.

Based on original changes from Mike Turquette.

Signed-off-by: Rajendra Nayak <rnayak@ti.com>
Cc: Russell King - ARM Linux <linux@arm.linux.org.uk>
[paul@pwsan.com: removed IS_ERR_OR_NULL() conversion (rmk comment);
 restricted omap_96m_alwon_fck_3630 to OMAP36xx; added missing AM35xx
 clock aliases for emac_fck, emac_ick, vpfe_ick, vpfe_fck; added
 aliases rng_ick and several emulation clocks]
Signed-off-by: Paul Walmsley <paul@pwsan.com>