crypto: nx - remove unused variables 'nx_driver_string' and 'nx_driver_version'

drivers/crypto/nx/nx.h:12:19: warning:
 nx_driver_string defined but not used [-Wunused-const-variable=]
drivers/crypto/nx/nx.h:13:19: warning:
 nx_driver_version defined but not used [-Wunused-const-variable=]

They are never used, so just remove it.
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

drivers/crypto/nx/nx.h

@@ -9,9 +9,6 @@
 #define NX_STRING	"IBM Power7+ Nest Accelerator Crypto Driver"
 #define NX_VERSION	"1.0"
 
-static const char nx_driver_string[] = NX_STRING;
-static const char nx_driver_version[] = NX_VERSION;
-
 /* a scatterlist in the format PHYP is expecting */
 struct nx_sg {
 	u64 addr;