arm64: defconfig: enable cma debugfs

Enable CONFIG_CMA_DEBUGFS for QGKI. This enables read only nodes on QGKI
build.  Enable CONFIG_CMA_ALLOW_WRITE_DEBUGFS for debug config. This
enables writeable cma debugfs node for debug build.

Change-Id: Ia40eea08c42b5c4d29691ea354411216c03e60a7
Signed-off-by: Prakash Gupta <guptap@codeaurora.org>