perf cs-etm: Remove duplicate GENMASK() define, use linux/bits.h instead

Suzuki noticed that this should be more useful in a generic header, and
after looking I noticed we have it already in our copy of
include/linux/bits.h in tools/include, so just use it, test built on
x86-64 and ubuntu 19.04 with:

  perfbuilder@46646c9e848e:/$ aarch64-linux-gnu-gcc --version |& head -1
  aarch64-linux-gnu-gcc (Ubuntu/Linaro 8.3.0-6ubuntu1) 8.3.0
  perfbuilder@46646c9e848e:/$

Suggested-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lkml.kernel.org/r/68c1c548-33cd-31e8-100d-7ffad008c7b2@arm.com
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: coresight@lists.linaro.org
Cc: linux-arm-kernel@lists.infradead.org,
Link: https://lkml.kernel.org/n/tip-69pd3mqvxdlh2shddsc7yhyv@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/cs-etm.h

@@ -9,6 +9,7 @@
 
 #include "util/event.h"
 #include "util/session.h"
+#include <linux/bits.h>
 
 /* Versionning header in case things need tro change in the future.  That way
  * decoding of old snapshot is still possible.
@@ -161,16 +162,6 @@ struct cs_etm_packet_queue {
 
 #define CS_ETM_INVAL_ADDR 0xdeadbeefdeadbeefUL
 
-/*
- * Create a contiguous bitmask starting at bit position @l and ending at
- * position @h. For example
- * GENMASK_ULL(39, 21) gives us the 64bit vector 0x000000ffffe00000.
- *
- * Carbon copy of implementation found in $KERNEL/include/linux/bitops.h
- */
-#define GENMASK(h, l) \
-	(((~0UL) - (1UL << (l)) + 1) & (~0UL >> (BITS_PER_LONG - 1 - (h))))
-
 #define BMVAL(val, lsb, msb)	((val & GENMASK(msb, lsb)) >> lsb)
 
 #define CS_ETM_HEADER_SIZE (CS_HEADER_VERSION_0_MAX * sizeof(u64))