OMAP2/3 clock: combine clkdm, clkdm_name into union in struct clk

struct clk contains a struct clockdomain *clkdm and const char
*clkdm_name.  The clkdm_name is only used at initialization to look up
the appropriate clkdm pointer.  Combining these into a union saves
about 850 bytes on 3430SDP.  This patch should not cause any change in
kernel function.

Boot-tested on 3430SDP ES2; compile-tested with n800_defconfig.

Signed-off-by: Paul Walmsley <paul@pwsan.com>
size:
   text    data     bss     dec     hex filename
3391555  157032  107136 3655723  37c82b vmlinux.3430sdp.orig
3391555  156176  107136 3654867  37c4d3 vmlinux.3430sdp
Signed-off-by: Tony Lindgren <tony@atomide.com>