linux-yocto: update genericx86* SRCREVs for v4.12

Bump to stable kernel release 4.12.20

(From meta-yocto rev: a3d67bf445f07b374ad47c2489706a3d50a7e474)

Signed-off-by: Anuj Mittal <anuj.mittal@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta-yocto-bsp/recipes-kernel/linux/linux-yocto_4.12.bbappend

@@ -8,8 +8,8 @@ KBRANCH_beaglebone-yocto = "standard/beaglebone"
 KMACHINE_beaglebone-yocto = "beaglebone"
 KBRANCH_mpc8315e-rdb = "standard/fsl-mpc8315e-rdb"
 
-SRCREV_machine_genericx86    ?= "257f843ea367744620f1d92910afd2f454e31483"
-SRCREV_machine_genericx86-64 ?= "257f843ea367744620f1d92910afd2f454e31483"
+SRCREV_machine_genericx86    ?= "1c4ad569af3e23a77994235435040e322908687f"
+SRCREV_machine_genericx86-64 ?= "1c4ad569af3e23a77994235435040e322908687f"
 SRCREV_machine_edgerouter ?= "257f843ea367744620f1d92910afd2f454e31483"
 SRCREV_machine_beaglebone-yocto ?= "257f843ea367744620f1d92910afd2f454e31483"
 SRCREV_machine_mpc8315e-rdb ?= "014560874f9eb2a86138c9cc35046ff1720485e1"
@@ -21,8 +21,8 @@ COMPATIBLE_MACHINE_edgerouter = "edgerouter"
 COMPATIBLE_MACHINE_beaglebone-yocto = "beaglebone-yocto"
 COMPATIBLE_MACHINE_mpc8315e-rdb = "mpc8315e-rdb"
 
-LINUX_VERSION_genericx86 = "4.12.19"
-LINUX_VERSION_genericx86-64 = "4.12.19"
+LINUX_VERSION_genericx86 = "4.12.20"
+LINUX_VERSION_genericx86-64 = "4.12.20"
 LINUX_VERSION_edgerouter = "4.12.19"
 LINUX_VERSION_beaglebone-yocto = "4.12.19"
 LINUX_VERSION_mpc8315e-rdb = "4.12.19"