linux-yocto/3.10: fix long perf compile times

perf's builtin-sched.c triggers extremly long build times on some
architectures due to gcc 4.7+ var-tracking functionality.

To fix this, we can cherry pick the 3.12 commit:

  f36f83f94 [perf sched: Move struct perf_sched definition out of cmd_sched()]

With this change build times are reduced from 15 to 20 minutes for qemuarm to:

  real    2m19.940s
  user    1m35.438s
  sys     0m11.165s

For kernel's that are not carrying this patch, the following can be added
to the perf recipe to also fix the issue:

    +++ b/meta/recipes-kernel/perf/perf.bb
    @@ -68,6 +68,7 @@ EXTRA_OEMAKE = \
		    CC="${CC}" \
		    AR="${AR}" \
		    perfexecdir=${libexecdir} \
    +               EXTRA_CFLAGS="-fno-var-tracking" \
		    NO_GTK2=1 ${TUI_DEFINES} NO_DWARF=1 ${SCRIPTING_DEFINES} \

(From OE-Core rev: 82ad5305381c2f541ef051a8fc28243cd91776fe)

Signed-off-by: Bruce Ashfield <bruce.ashfield@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-kernel/linux/linux-yocto-rt_3.10.bb

@@ -3,8 +3,8 @@ require recipes-kernel/linux/linux-yocto.inc
 KBRANCH = "standard/preempt-rt/base"
 KBRANCH_qemuppc = "standard/preempt-rt/qemuppc"
 
-SRCREV_machine ?= "4de6b6b24c44ef644b46405a85c550128d4a779a"
-SRCREV_machine_qemuppc ?= "24a1786e5ed0d479638af5738375e396bf4c922c"
+SRCREV_machine ?= "f1e003e9441f0366d7b9a2209ef3108438745ea3"
+SRCREV_machine_qemuppc ?= "12be459359d5b20dbf856aa3649304c6f618d420"
 SRCREV_meta ?= "4f689aa30a2c9cf5dceb2fa3696d2cb208ee9173"
 
 SRC_URI = "git://git.yoctoproject.org/linux-yocto-3.10.git;bareclone=1;branch=${KBRANCH},meta;name=machine,meta"