mailbox: qcom: Use PLATFORM_DEVID_AUTO to register platform device

In adding APCS clock support for MSM8939, the second clock registration
fails due to duplicate device name like below.

[    0.519657] sysfs: cannot create duplicate filename '/bus/platform/devices/qcom-apcs-msm8916-clk'
...
[    0.661158] qcom_apcs_ipc b111000.mailbox: failed to register APCS clk

This is because MSM8939 has 3 APCS instances for Cluster0 (little cores),
Cluster1 (big cores) and CCI (Cache Coherent Interconnect).  Although
only APCS of Cluster0 and Cluster1 have IPC bits, each of 3 APCS has
A53PLL clock control bits.  That said, 3 'qcom-apcs-msm8916-clk' devices
need to be registered to instantiate all 3 clocks.  Use PLATFORM_DEVID_AUTO
rather than PLATFORM_DEVID_NONE for platform_device_register_data() call
to fix the issue above.

Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>