Nokia RX-51: Add check for /lib/ld-linux.so.2 in test script

Unfortunately for testing is required qflasher which works only in 32-bit
x86 mode. Apparently 64-bit x86 Azure CI has no problems as it has
preinstalled 32-bit libraries and can execute also 32-bit x86 executables.

This change just show human readable output why nokia_rx51_test.sh test
script fails.

Signed-off-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>
Link: https://lore.kernel.org/r/20210618133108.32497-1-pali@kernel.org