nvme: fix libuuid test when cross compiling

Use $(LD) to test whether libuuid is installed, so that we check the target,
not the host.

Fixes:
http://autobuild.buildroot.net/results/e26/e263ffbf8947374c2aac73ab42edcbf4d9a3600a/
http://autobuild.buildroot.net/results/53b/53b2d1e0c3cdeafb980389bcfd8a10b6ca48fbc2/



Cc: Mamatha Inamdar <mamatha4@linux.vnet.ibm.com>
Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>