clocksource: Move inline keyword to the beginning of function declarations

The inline keyword was not at the beginning of the function declarations.
Fix the following warnings triggered when using W=1:

  kernel/time/clocksource.c:108:1: warning: 'inline' is not at beginning of declaration [-Wold-style-declaration]
  kernel/time/clocksource.c:113:1: warning: 'inline' is not at beginning of declaration [-Wold-style-declaration]

Signed-off-by: Mathieu Malaterre <malat@debian.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: trivial@kernel.org
Cc: kernel-janitors@vger.kernel.org
Cc: John Stultz <john.stultz@linaro.org>
Cc: Stephen Boyd <sboyd@kernel.org>
Link: https://lkml.kernel.org/r/20190524103339.28787-1-malat@debian.org