libvpx: don't specify armv5 and armv6 toolchains explicitly

The libvpx project has removed the support for these values, and
the recipe can't be built anymore for these arch's when these values
are used. The correct value for these arch's is `generic-gnu`,
which is used as a default fallthrough value for all platforms
in the recipe for arch's that are not specified explicitly.

Signed-off-by: Khem Raj <raj.khem@gmail.com>

meta-oe/recipes-multimedia/webm/libvpx_1.13.1.bb

@@ -24,8 +24,6 @@ BUILD_LDFLAGS += "-pthread"
 export CC
 export LD = "${CC}"
 
-VPXTARGET:armv5te = "armv5te-linux-gcc"
-VPXTARGET:armv6 = "armv6-linux-gcc"
 VPXTARGET:armv7a = "${@bb.utils.contains("TUNE_FEATURES","neon","armv7-linux-gcc","generic-gnu",d)}"
 VPXTARGET ?= "generic-gnu"