Similar to the previous patch, the APLL code relied on the presence of the
static struct clks in its own namespace.  The APLL code didn't use them for
validation, however - it adjusted its own internal state depending on
the struct clk * that called it.  Now that static struct clks are
leaving the clock24xx.c namespace, use a more durable method: split the
omap2_clk_fixed_enable() function into omap2_clk_apll96_enable() and
omap2_clk_apll54_enable().  They still share a disable function.
Signed-off-by: Paul Walmsley <paul@pwsan.com>