clk: ti: Silence sparse warnings

drivers/clk/ti/clk.c:125:31: warning: incorrect type in return expression (different address spaces)
drivers/clk/ti/clk.c:125:31:    expected void [noderef] <asn:2>*
drivers/clk/ti/clk.c:125:31:    got void *
drivers/clk/ti/clk.c:132:31: warning: incorrect type in return expression (different address spaces)
drivers/clk/ti/clk.c:132:31:    expected void [noderef] <asn:2>*
drivers/clk/ti/clk.c:132:31:    got void *
drivers/clk/ti/dpll.c:180:14: warning: symbol '_get_reg' was not declared. Should it be static?
drivers/clk/ti/fapll.c:624:32: warning: Using plain integer as NULL pointer
drivers/clk/ti/fapll.c:625:31: warning: Using plain integer as NULL pointer
drivers/clk/ti/fapll.c:630:40: warning: Using plain integer as NULL pointer
drivers/clk/ti/clk-dra7-atl.c:158:22: warning: symbol 'atl_clk_ops' was not declared. Should it be static?
drivers/clk/ti/clk-dra7-atl.c:170:39: warning: Using plain integer as NULL pointer

Acked-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Acked-by: Tero Kristo <t-kristo@ti.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>