openssh-server: manually set path to passwd binary

In the build environment the autotools finds the `passwd` binary in
/usr/bin. But in the target image it is available under /bin instead.
Manually set the path to `passwd` binary to `/bin/passwd`

Signed-off-by: Rucke Teg <rucketeg@protonmail.com>

net/openssh/Makefile

@@ -183,7 +183,7 @@ CONFIGURE_ARGS += \
 	--without-pam
 endif
 
-CONFIGURE_VARS += LD="$(TARGET_CC)"
+CONFIGURE_VARS += LD="$(TARGET_CC)" PATH_PASSWD_PROG="/bin/passwd"
 
 ifeq ($(BUILD_VARIANT),with-pam)
 TARGET_LDFLAGS += -lpthread