hwrng: st - add MODULE_DESCRIPTION

Add a MODULE_DESCRIPTION to fix the W=1 warning

WARNING: modpost: missing MODULE_DESCRIPTION() in
drivers/char/hw_random/st-rng.o
Signed-off-by: Martin Kaiser <martin@kaiser.cx>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

drivers/char/hw_random/st-rng.c

@@ -121,4 +121,5 @@ static struct platform_driver st_rng_driver = {
 module_platform_driver(st_rng_driver);
 
 MODULE_AUTHOR("Pankaj Dev <pankaj.dev@st.com>");
+MODULE_DESCRIPTION("ST Microelectronics HW Random Number Generator");
 MODULE_LICENSE("GPL v2");