rdma: Fix broken 32-bit compilation

rdma: Fix broken 32-bit compilation

Allow compilation of rdmatool on 32-bits platforms.

rdma
    CC       rdma.o
    CC       utils.o
    CC       dev.o
    CC       link.o
In file included from rdma.h:26:0,
                 from dev.c:12:
dev.c: In function 'dev_caps_tostr':
../include/utils.h:269:38: warning: left shift count >= width of type [-Wshift-count-overflow]
 #define BIT(nr)                 (1UL << (nr))
                                      ^
rdma.h:32:61: note: in expansion of macro 'BIT'
 #define RDMA_BITMAP_ENUM(name, bit_no) RDMA_BITMAP_##name = BIT(bit_no),
                                                             ^~~

Fixes: 40df8263a0f0 ("rdma: Add dev object")
Reported-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>