autotools: remove aclocal --automake-acdir, relocated so knows the right path

autotools: remove aclocal --automake-acdir, relocated so knows the right path

A relocated aclocal in the native sysroot has the right paths already:

$ cat /work/ross/build/tmp/work/cortexa57-poky-linux/expect/5.45.4/recipe-sysroot-native/usr/bin/aclocal
my @automake_includes = ('/work/ross/build/tmp/work/cortexa57-poky-linux/expect/5.45.4/recipe-sysroot-native/usr/share/aclocal-' . $APIVERSION);

Thus there is no need to tell aclocal the path explicitly.

Signed-off-by: Ross Burton <ross.burton@arm.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>