sh: clkfwk: Kill off unused clk_set_rate_ex().

With the refactoring of the SH7722 clock framework some time ago this
abstraction has become unecessary. Kill it off before anyone else gets
the bright idea to start using it.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>

Documentation/sh/clk.txt

@@ -1,32 +0,0 @@
-Clock framework on SuperH architecture
-
-The framework on SH extends existing API by the function clk_set_rate_ex,
-which prototype is as follows:
-
-    clk_set_rate_ex (struct clk *clk, unsigned long rate, int algo_id)
-
-The algo_id parameter is used to specify algorithm used to recalculate clocks,
-adjanced to clock, specified as first argument. It is assumed that algo_id==0
-means no changes to adjanced clock
-
-Internally, the clk_set_rate_ex forwards request to clk->ops->set_rate method,
-if it is present in ops structure. The method should set the clock rate and adjust
-all needed clocks according to the passed algo_id.
-Exact values for algo_id are machine-dependent. For the sh7722, the following
-values are defined:
-
-	NO_CHANGE	= 0,
-	IUS_N1_N1,	/* I:U = N:1, U:Sh = N:1 */
-	IUS_322,	/* I:U:Sh = 3:2:2	 */
-	IUS_522,	/* I:U:Sh = 5:2:2 	 */
-	IUS_N11,	/* I:U:Sh = N:1:1	 */
-	SB_N1,		/* Sh:B = N:1		 */
-	SB3_N1,		/* Sh:B3 = N:1		 */
-	SB3_32,		/* Sh:B3 = 3:2		 */
-	SB3_43,		/* Sh:B3 = 4:3		 */
-	SB3_54,		/* Sh:B3 = 5:4		 */
-	BP_N1,		/* B:P	 = N:1		 */
-	IP_N1		/* I:P	 = N:1		 */
-
-Each of these constants means relation between clocks that can be set via the FRQCR
-register