[qib7322] Avoid unused variable warning in gcc 4.6

Reported-by: Ralph Giles <giles@thaumas.net>
Tested-by: Ralph Giles <giles@thaumas.net>
Signed-off-by: Michael Brown <mcb30@ipxe.org>

src/drivers/infiniband/qib7322.c

 	unsigned long egrbase;
 	unsigned int eager_array_size_kernel;
 	unsigned int eager_array_size_user;
-	unsigned int user_context_mask;
 	unsigned int ctx;
 
 	/* Select configuration based on number of contexts */
 		contextcfg = QIB7322_CONTEXTCFG_6CTX;
 		eager_array_size_kernel = QIB7322_EAGER_ARRAY_SIZE_6CTX_KERNEL;
 		eager_array_size_user = QIB7322_EAGER_ARRAY_SIZE_6CTX_USER;
-		user_context_mask = 0x000f;
 		break;
 	case 10:
 		contextcfg = QIB7322_CONTEXTCFG_10CTX;
 		eager_array_size_kernel = QIB7322_EAGER_ARRAY_SIZE_10CTX_KERNEL;
 		eager_array_size_user = QIB7322_EAGER_ARRAY_SIZE_10CTX_USER;
-		user_context_mask = 0x00ff;
 		break;
 	case 18:
 		contextcfg = QIB7322_CONTEXTCFG_18CTX;
 		eager_array_size_kernel = QIB7322_EAGER_ARRAY_SIZE_18CTX_KERNEL;
 		eager_array_size_user = QIB7322_EAGER_ARRAY_SIZE_18CTX_USER;
-		user_context_mask = 0xffff;
 		break;
 	default:
 		linker_assert ( 0, invalid_QIB7322_NUM_CONTEXTS );