qemu: enable ION unmapped heap test support in kernel config

Latest changes in ION requires CONFIG_ION_UNMAPPED_HEAP to configure
the support for unmapped heap.

Signed-off-by: Etienne Carriere <etienne.carriere@linaro.org>
Reviewed-by: Joakim Bech <joakim.bech@linaro.org>

kconfigs/qemu.conf

@@ -3,6 +3,7 @@ CONFIG_OPTEE=y
 CONFIG_STAGING=y
 CONFIG_ION=y
 CONFIG_ION_DUMMY=y
+CONFIG_ION_UNMAPPED_HEAP=y
 CONFIG_ION_DUMMY_UNMAPPED_HEAP=y
 CONFIG_ION_DUMMY_UNMAPPED_BASE=0x0ec00000
 CONFIG_ION_DUMMY_UNMAPPED_SIZE=0x00400000