clk: pxa mark dummy helper as 'inline'

clk: pxa mark dummy helper as 'inline'

The dummy_clk_set_parent function is marked as 'static' but is
no longer referenced from the pxa25x clk driver after the last use
of the RATE_RO_OPS() macro is gone from this file, causing a
harmless build warning:

In file included from drivers/clk/pxa/clk-pxa25x.c:24:0:
drivers/clk/pxa/clk-pxa.h:146:12: error: 'dummy_clk_set_parent' defined but not used [-Werror=unused-function]

This marks the functon as 'inline', which lets the compiler simply
drop it when it gets referenced.

Fixes: 9fe694295098 ("clk: pxa: transfer CPU clock setting from pxa2xx-cpufreq")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>