cpufreq: intel_pstate: remove obsolete functions

percent_fp() was used in intel_pstate_pid_reset(), which was removed in
commit 9d0ef7af ("cpufreq: intel_pstate: Do not use PID-based P-state
selection") and hence, percent_fp() is unused since then.

percent_ext_fp() was last used in intel_pstate_update_perf_limits(), which
was refactored in commit 1a4fe38a ("cpufreq: intel_pstate: Remove
max/min fractions to limit performance"), and hence, percent_ext_fp() is
unused since then.

make CC=clang W=1 points us those unused functions:

drivers/cpufreq/intel_pstate.c:79:23: warning: unused function 'percent_fp' [-Wunused-function]
static inline int32_t percent_fp(int percent)
                      ^

drivers/cpufreq/intel_pstate.c:94:23: warning: unused function 'percent_ext_fp' [-Wunused-function]
static inline int32_t percent_ext_fp(int percent)
                      ^

Remove those obsolete functions.

Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>