clk: x86: lpss-atom: Drop unneeded 'extern' in the header

'extern' for the functions is not needed, drop it.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20231208165238.3309058-1-andriy.shevchenko@linux.intel.comReviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

include/linux/platform_data/x86/clk-lpss.h

@@ -15,6 +15,6 @@ struct lpss_clk_data {
 	struct clk *clk;
 };
 
-extern int lpss_atom_clk_init(void);
+int lpss_atom_clk_init(void);
 
 #endif /* __CLK_LPSS_H */