ANDROID: fix up platform_device ABI break

In commit 389190b2 ("driver: platform: Add helper for safer setting
of driver_override"), a pointer was changed to const, which messes with
the CRC and ABI checks.  As the code is fine if this is left as
not-const, just put it back to preserve the abi.

Bug: 161946584
Fixes: 389190b2 ("driver: platform: Add helper for safer setting of driver_override")
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: Ieb4a730a6a5767d31fbec2f1ba683617f5cda7a9