Revert "remoteproc: stm32: Fix incorrect type in assignment for va"

This reverts commit 0dd5b63a which is
commit 32381bbc upstream.

It breaks the Android kernel abi and can be brought back in the future
in an abi-safe way if it is really needed.

Bug: 161946584
Change-Id: Ic7512dc88e8c32c3adc7fec73f4cc0c89fd58c80
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>