perf/x86/intel: Mark expected switch fall-throughs

In preparation to enabling -Wimplicit-fallthrough, mark switch
cases where we are expecting to fall through.

This patch fixes the following warnings:

arch/x86/events/intel/core.c: In function ‘intel_pmu_init’:
arch/x86/events/intel/core.c:4959:8: warning: this statement may fall through [-Wimplicit-fallthrough=]
arch/x86/events/intel/core.c:5008:8: warning: this statement may fall through [-Wimplicit-fallthrough=]

Warning level 3 was used: -Wimplicit-fallthrough=3

This patch is part of the ongoing efforts to enable -Wimplicit-fallthrough.

Signed-off-by: Gustavo A. R. Silva <[e-mail]>
Signed-off-by: Peter Zijlstra (Intel) <[e-mail]>
Cc: Alexander Shishkin <[e-mail]>
Cc: Arnaldo Carvalho de Melo <[e-mail]>
Cc: Borislav Petkov <[e-mail]>
Cc: H. Peter Anvin <[e-mail]>
Cc: Jiri Olsa <[e-mail]>
Cc: Kan Liang <[e-mail]>
Cc: Kees Cook <[e-mail]>
Cc: Linus Torvalds <[e-mail]>
Cc: Namhyung Kim <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Cc: Thomas Gleixner <[e-mail]>
Link: https://lkml.kernel.org/r/20190624161913.GA32270@embeddedor
Signed-off-by: Ingo Molnar <[e-mail]>

arch/x86/events/intel/core.c

···
 
 	case INTEL_FAM6_SKYLAKE_X:
 		pmem = true;
+		/* fall through */
 	case INTEL_FAM6_SKYLAKE_MOBILE:
 	case INTEL_FAM6_SKYLAKE_DESKTOP:
 	case INTEL_FAM6_KABYLAKE_MOBILE:
···
 	case INTEL_FAM6_ICELAKE_X:
 	case INTEL_FAM6_ICELAKE_XEON_D:
 		pmem = true;
+		/* fall through */
 	case INTEL_FAM6_ICELAKE_MOBILE:
 	case INTEL_FAM6_ICELAKE_DESKTOP:
 		x86_pmu.late_ack = true;