tune-cortexa32: set tune feature as armv8a

Cortexa32 is a 32-bit armv8a architecture processor, so set the tune feature
as armv8a instead of aarch64 which is 64-bit armv8a architecture.

It solves the following build error while compiling libgcc-initial
and libssp-nonshared.
-- snip --
aarch64-poky-linux-musl-gcc: error: unrecognized command-line option '-mfpu=neon'
aarch64-poky-linux-musl-gcc: error: unrecognized command-line option '-mfloat-abi=hard'
-- snip --

(From OE-Core rev: a83ead146c15772970c7ca649e81929302349033)

Signed-off-by: Jagadeesh Krishnanjanappa <workjagadeesh@gmail.com>
Signed-off-by: Mathieu Dubois-Briand <mathieu.dubois-briand@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
(cherry picked from commit 3b898270aca62559dfa42ed71d296fe8a8b46a41)
Signed-off-by: Steve Sakoman <steve@sakoman.com>

meta/conf/machine/include/arm/armv8a/tune-cortexa32.inc

@@ -10,7 +10,7 @@ AVAILTUNES += "cortexa32 cortexa32-crypto"
 ARMPKGARCH:tune-cortexa32             = "cortexa32"
 ARMPKGARCH:tune-cortexa32-crypto      = "cortexa32"
 # We do not want -march since -mcpu is added above to cover for it
-TUNE_FEATURES:tune-cortexa32          = "aarch64 cortexa32 crc callconvention-hard neon"
+TUNE_FEATURES:tune-cortexa32          = "armv8a cortexa32 crc callconvention-hard neon"
 TUNE_FEATURES:tune-cortexa32-crypto   = "${TUNE_FEATURES:tune-cortexa32} crypto"
 PACKAGE_EXTRA_ARCHS:tune-cortexa32             = "${PACKAGE_EXTRA_ARCHS:tune-armv8a-crc} cortexa32 cortexa32hf-neon"
 PACKAGE_EXTRA_ARCHS:tune-cortexa32-crypto      = "${PACKAGE_EXTRA_ARCHS:tune-armv8a-crc-crypto} cortexa32 cortexa32hf-neon cortexa32hf-neon-crypto"