deb-pkg: Fix building for MIPS big-endian or ARM OABI

These commands will mysteriously fail:

$ make ARCH=arm versatile_defconfig
[...]
$ make ARCH=arm deb-pkg
[...]
make[1]: *** [deb-pkg] Error 1
make: *** [deb-pkg] Error 2

The Debian architecture selection for these kernel architectures does
'grep FOO=y $KCONFIG_CONFIG && echo bar', and after 'set -e' this
aborts the script if grep does not find the given config symbol.

Fixes: 10f26fa64200 ('build, deb-pkg: select userland architecture based on UTS_MACHINE')
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Michal Marek <mmarek@suse.cz>

scripts/package/builddeb

@@ -41,9 +41,9 @@ create_package() {
 	parisc*)
 		debarch=hppa ;;
 	mips*)
-		debarch=mips$(grep -q CPU_LITTLE_ENDIAN=y $KCONFIG_CONFIG && echo el) ;;
+		debarch=mips$(grep -q CPU_LITTLE_ENDIAN=y $KCONFIG_CONFIG && echo el || true) ;;
 	arm*)
-		debarch=arm$(grep -q CONFIG_AEABI=y $KCONFIG_CONFIG && echo el) ;;
+		debarch=arm$(grep -q CONFIG_AEABI=y $KCONFIG_CONFIG && echo el || true) ;;
 	*)
 		echo "" >&2
 		echo "** ** **  WARNING  ** ** **" >&2