ARM: perf: Mark all accessor functions inline

ARM: perf: Mark all accessor functions inline

When just including <asm/arm_pmuv3.h>:

    arch/arm/include/asm/arm_pmuv3.h:110:13: error: ‘write_pmevtypern’ defined but not used [-Werror=unused-function]
      110 | static void write_pmevtypern(int n, unsigned long val)
	  |             ^~~~~~~~~~~~~~~~
    arch/arm/include/asm/arm_pmuv3.h:103:13: error: ‘write_pmevcntrn’ defined but not used [-Werror=unused-function]
      103 | static void write_pmevcntrn(int n, unsigned long val)
	  |             ^~~~~~~~~~~~~~~
    arch/arm/include/asm/arm_pmuv3.h:95:22: error: ‘read_pmevcntrn’ defined but not used [-Werror=unused-function]
       95 | static unsigned long read_pmevcntrn(int n)
	  |                      ^~~~~~~~~~~~~~

Fix this by adding the missing "inline" keywords to the three accessor
functions that lack them.

Fixes: 009d6dc87a56 ("ARM: perf: Allow the use of the PMUv3 driver on 32bit ARM")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/3a7d9bc7470aa2d85696ee9765c74f8c03fb5454.1683561482.git.geert+renesas@glider.be
Signed-off-by: Will Deacon <will@kernel.org>