qemu conf: enable ION for OP-TEE/SDP test support

Enable Linux kernel ION, ION_DUMMY.
Statically define an 3MByte unmapped heap in ION dummy driver. This
complies with the OP-TEE layout for qemu_virt and qemu_armv8 platforms.

CONFIG_ION has dependencies on CONFIG_ANDROID. This changes enables
ION from the Android staging drivers but without enabling other
staged Android features (TIMED_OUTPUT and LOW_MEMORY_KILLER).

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

kconfigs/qemu.conf

 CONFIG_TEE=y
 CONFIG_OPTEE=y
+CONFIG_STAGING=y
+CONFIG_ION=y
+CONFIG_ION_DUMMY=y
+CONFIG_ION_DUMMY_UNMAPPED_HEAP=y
+CONFIG_ION_DUMMY_UNMAPPED_BASE=0x0e000000
+CONFIG_ION_DUMMY_UNMAPPED_SIZE=0x00300000
+CONFIG_ANDROID=y
+CONFIG_ANDROID_TIMED_OUTPUT=n
+CONFIG_ANDROID_LOW_MEMORY_KILLER=n
 ### Enabling PREEMPT and disabling JFFS2_FS prevents random failures of
 ### "make check" in Travis CI
 CONFIG_PREEMPT=y