fix update-makefiles.sh to not need Android.mk

When auto-generating Android.mk for HIDL packages, update-makefiles.sh
now just looks for all directories hosting .hal files, converts them to
HIDL package names, and invokes hidl-gen on these package names to
generate the appropriate Android.mk files.

Change-Id: I8a824672f33be58508ae7c07de463f4f589a9a73
Signed-off-by: Iliyan Malchev <malchev@google.com>

update-makefiles.sh

@@ -6,7 +6,7 @@ if [ ! -d hardware/interfaces ] ; then
 fi
 
 packages=$(pushd hardware/interfaces > /dev/null; \
-           find . -type f -name Android.mk -exec dirname {} \; | \
+           find . -type f -name \*.hal -exec dirname {} \; | sort -u | \
            cut -c3- | \
            awk -F'/' \
                 '{printf("android.hardware"); for(i=1;i<NF;i++){printf(".%s", $i);}; printf("@%s\n", $NF);}'; \