meta-yocto-bsp: Remove superfluous OVERRIDES in machine conf files

In machine configuration files, there is no need to use OVERRIDES that
match the precise machine being defined, so remove them for clarity
and consistency from these lines in those respective files:

  PREFERRED_VERSION_linux-yocto_genericx86-64 ?= "4.10%"
  PREFERRED_VERSION_linux-yocto_genericx86 ?= "4.10%"
  UBOOT_MACHINE_mpc8315e-rdb = "MPC8315ERDB_config"

(From meta-yocto rev: 035d4e7763171068d2b4df0622b6cc0fc1cf4b32)

Signed-off-by: Robert P. J. Day <rpjday@crashcourse.ca>
Signed-off-by: Ross Burton <ross.burton@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta-yocto-bsp/conf/machine/genericx86-64.conf

@@ -7,6 +7,6 @@ DEFAULTTUNE ?= "core2-64"
 require conf/machine/include/tune-core2.inc
 require conf/machine/include/genericx86-common.inc
 
-PREFERRED_VERSION_linux-yocto_genericx86-64 ?= "4.10%"
+PREFERRED_VERSION_linux-yocto ?= "4.10%"
 
 SERIAL_CONSOLES_CHECK = "ttyS0"

meta-yocto-bsp/conf/machine/genericx86.conf

@@ -9,4 +9,4 @@ require conf/machine/include/genericx86-common.inc
 
 MACHINE_ESSENTIAL_EXTRA_RRECOMMENDS += "gma500-gfx-check"
 
-PREFERRED_VERSION_linux-yocto_genericx86 ?= "4.10%"
+PREFERRED_VERSION_linux-yocto ?= "4.10%"

meta-yocto-bsp/conf/machine/mpc8315e-rdb.conf

@@ -8,7 +8,7 @@ require conf/machine/include/tune-ppce300c3.inc
 KERNEL_IMAGETYPE = "uImage"
 
 EXTRA_IMAGEDEPENDS += "u-boot"
-UBOOT_MACHINE_mpc8315e-rdb = "MPC8315ERDB_config"
+UBOOT_MACHINE = "MPC8315ERDB_config"
 
 SERIAL_CONSOLE = "115200 ttyS0"