staging: vchiq_core: get the rid of IS_POW2

The macro IS_POW2 is only used to ensure some size are powers of 2.
Better use BUILD_BUG_ON_NOT_POWER_OF_2 for this. Since this must be done
in a function, merge all these checks in a new function.

Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
Link: https://lore.kernel.org/r/1622735405-9980-5-git-send-email-stefan.wahren@i2se.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>