perf bench: Default to all routines in 'perf bench mem'

So few people know that the --routine option to 'perf bench memcpy/memset'
exists, and would not know that it's capable of testing the kernel's
memcpy/memset implementations.

Furthermore, 'perf bench mem all' will not run all routines:

	vega:~> perf bench mem all
	# Running mem/memcpy benchmark...
	Routine default (Default memcpy() provided by glibc)
	# Copying 1MB Bytes ...

	     894.454383 MB/Sec
	       3.844734 GB/Sec (with prefault)

	# Running mem/memset benchmark...
	Routine default (Default memset() provided by glibc)
	# Copying 1MB Bytes ...

	       1.220703 GB/Sec
	       9.042245 GB/Sec (with prefault)

Because misleadingly the 'all' refers to 'all sub-benchmarks', not 'all
sub-benchmarks and routines'.

Fix all this by making the memcpy/memset routine to default to 'all',
which results in all the benchmarks being run:

	triton:~> perf bench mem all
	# Running mem/memcpy benchmark...
	Routine default (Default memcpy() provided by glibc)
	# Copying 1MB Bytes ...

	       1.448906 GB/Sec
	       4.957170 GB/Sec (with prefault)
	Routine x86-64-unrolled (unrolled memcpy() in arch/x86/lib/memcpy_64.S)
	# Copying 1MB Bytes ...

	       1.614153 GB/Sec
	       4.379204 GB/Sec (with prefault)
	Routine x86-64-movsq (movsq-based memcpy() in arch/x86/lib/memcpy_64.S)
	# Copying 1MB Bytes ...

	       1.570036 GB/Sec
	       4.264465 GB/Sec (with prefault)
	Routine x86-64-movsb (movsb-based memcpy() in arch/x86/lib/memcpy_64.S)
	# Copying 1MB Bytes ...

	       1.788576 GB/Sec
	       6.554111 GB/Sec (with prefault)

	# Running mem/memset benchmark...
	Routine default (Default memset() provided by glibc)
	# Copying 1MB Bytes ...

	       2.082223 GB/Sec
	       9.126752 GB/Sec (with prefault)
	Routine x86-64-unrolled (unrolled memset() in arch/x86/lib/memset_64.S)
	# Copying 1MB Bytes ...

	       5.710892 GB/Sec
	       8.346688 GB/Sec (with prefault)
	Routine x86-64-stosq (movsq-based memset() in arch/x86/lib/memset_64.S)
	# Copying 1MB Bytes ...

	       9.765625 GB/Sec
	      12.520032 GB/Sec (with prefault)
	Routine x86-64-stosb (movsb-based memset() in arch/x86/lib/memset_64.S)
	# Copying 1MB Bytes ...

	       9.668936 GB/Sec
	      12.682630 GB/Sec (with prefault)

Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Hitoshi Mitake <mitake@dcl.info.waseda.ac.jp>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1445241870-24854-3-git-send-email-mingo@kernel.org


Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>