php7: add dependency to hash for mysqlnd

The following error shows that mysqlnd depends on functions
provided by hash:

root@OpenWrt:/etc/php7# php-cli -m
PHP Warning:  PHP Startup: Unable to load dynamic library
'mysqlnd.so' (tried: /usr/lib/php/mysqlnd.so (Error
relocating /usr/lib/php/mysqlnd.so: PHP_SHA256Final: symbol
not found), /usr/lib/php/mysqlnd.so.so (Error loading shared
library /usr/lib/php/mysqlnd.so.so: No such file or
directory)) in Unknown on line 0

So let's model this dep in package metadata.

Signed-off-by: Michael Heimpold <mhei@heimpold.de>

lang/php7/Makefile

@@ -7,7 +7,7 @@ include $(TOPDIR)/rules.mk
 
 PKG_NAME:=php
 PKG_VERSION:=7.2.8
-PKG_RELEASE:=1
+PKG_RELEASE:=2
 
 PKG_MAINTAINER:=Michael Heimpold <mhei@heimpold.de>
 
@@ -608,7 +608,7 @@ $(eval $(call BuildModule,json,JSON))
 $(eval $(call BuildModule,ldap,LDAP,+PACKAGE_php7-mod-ldap:libopenldap +PACKAGE_php7-mod-ldap:libsasl2))
 $(eval $(call BuildModule,mbstring,MBString))
 $(eval $(call BuildModule,mysqli,MySQL Improved Extension,+PACKAGE_php7-mod-mysqli:php7-mod-mysqlnd,30))
-$(eval $(call BuildModule,mysqlnd,MySQL Native Driver))
+$(eval $(call BuildModule,mysqlnd,MySQL Native Driver,+php7-mod-hash))
 $(eval $(call BuildModule,opcache,OPcache,,,zend))
 $(eval $(call BuildModule,openssl,OpenSSL,+PACKAGE_php7-mod-openssl:libopenssl))
 $(eval $(call BuildModule,pcntl,PCNTL))