rds: fix compilation warnings

rds: fix compilation warnings

net/rds/ib_recv.c: In function 'rds_ib_srq_event':
net/rds/ib_recv.c:1490: warning: too many arguments for format
net/rds/ib_recv.c:1484: warning: unused variable 'srq_attr'
net/rds/ib_recv.c: In function 'rds_ib_srq_init':
net/rds/ib_recv.c:1524: warning: passing argument 1 of 'ERR_PTR' makes
integer from pointer without a cast
include/linux/err.h:20: note: expected 'long int' but argument is of
type 'struct ib_srq *'
net/rds/ib_recv.c:1524: warning: format '%d' expects type 'int', but
argument 2 has type 'void *'

Signed-off-by: Dotan Barak <dotanb@dev.mellanox.co.il>