LU-12904 build: External _module_ decorator removed

LU-12904 build: External _module_ decorator removed

As of 5.4 the _module_ decorator prefix is not used for external
kernel modules. This breaks building kernel modules for 5.4.
Prior kernels still require the _module_ decorator.

Add a configure check to test for and handle _module_ decorator is
used.

Linux-commit: d7b0827f28ab3a4fd65864451ffefa695e3255fd

Test-Parameters: trivial
Cray-bug-id: LUS-8042
Signed-off-by: Shaun Tancheff <stancheff@cray.com>
Change-Id: I4359452cea8e32a31234b9becc2ed319954c55a4
Reviewed-on: https://review.whamcloud.com/36576
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Petros Koutoupis <pkoutoupis@cray.com>
Reviewed-by: James Simmons <jsimmons@infradead.org>
Reviewed-by: Oleg Drokin <green@whamcloud.com>