x86/events: Mark expected switch-case fall-throughs

In preparation to enable -Wimplicit-fallthrough by default, mark
switch-case statements where fall-through is intentional, explicitly in
order to fix a couple of -Wimplicit-fallthrough warnings.

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

 [ bp: Massasge and trim commit message. ]
Signed-off-by: NGustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: NBorislav Petkov <bp@suse.de>
Acked-by: NPeter Zijlstra <peterz@infradead.org>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jacek Tomaka <jacek.tomaka@poczta.fm>
Cc: Jia Zhang <qianyue.zj@alibaba-inc.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: x86-ml <x86@kernel.org>
Link: https://lkml.kernel.org/r/20190125184917.GA7289@embeddedor

arch/x86/events/intel/core.c

@@ -4168,6 +4168,8 @@ __init int intel_pmu_init(void)
 
 	case INTEL_FAM6_CORE2_MEROM:
 		x86_add_quirk(intel_clovertown_quirk);
+		/* fall through */
+
 	case INTEL_FAM6_CORE2_MEROM_L:
 	case INTEL_FAM6_CORE2_PENRYN:
 	case INTEL_FAM6_CORE2_DUNNINGTON:

arch/x86/events/intel/lbr.c

@@ -931,6 +931,7 @@ static int branch_type(unsigned long from, unsigned long to, int abort)
 			ret = X86_BR_ZERO_CALL;
 			break;
 		}
+		/* fall through */
 	case 0x9a: /* call far absolute */
 		ret = X86_BR_CALL;
 		break;