clk: spear: Add stub functions for spear3[0|1|2]0_clk_init()

This fixes compile error if one of SPEAr3xx implementations is not selected.

CC drivers/clk/spear/spear3xx_clock.o
drivers/clk/spear/spear3xx_clock.c: In function 'spear3xx_clk_init':
drivers/clk/spear/spear3xx_clock.c:599:3: error: implicit declaration of function 'spear300_clk_init' [-Werror=implicit-function-declaration]
drivers/clk/spear/spear3xx_clock.c:601:3: error: implicit declaration of function 'spear310_clk_init' [-Werror=implicit-function-declaration]
drivers/clk/spear/spear3xx_clock.c:603:3: error: implicit declaration of function 'spear320_clk_init' [-Werror=implicit-function-declaration]
cc1: some warnings being treated as errors
make[3]: *** [drivers/clk/spear/spear3xx_clock.o] Error 1
make[2]: *** [drivers/clk/spear] Error 2
make[1]: *** [drivers/clk] Error 2
make: *** [drivers] Error 2

Signed-off-by: Axel Lin <[e-mail]>
Acked-by: Viresh Kumar <[e-mail]>
Signed-off-by: Mike Turquette <[e-mail]>

drivers/clk/spear/spear3xx_clock.c

···
 			1);
 	clk_register_clkdev(clk, NULL, "a0000000.kbd");
 }
+#else
+static inline void spear300_clk_init(void) { }
 #endif
 
 /* array of all spear 310 clock lookups */
···
 			1);
 	clk_register_clkdev(clk, NULL, "b2200000.serial");
 }
+#else
+static inline void spear310_clk_init(void) { }
 #endif
 
 /* array of all spear 320 clock lookups */
···
 			&_lock);
 	clk_register_clkdev(clk, NULL, "60100000.serial");
 }
+#else
+static inline void spear320_clk_init(void) { }
 #endif
 
 void __init spear3xx_clk_init(void)