RDMA/bnxt_re: Fix clang -Wimplicit-fallthrough in bnxt_re_handle_cq_async_error()

Clang warns (or errors with CONFIG_WERROR=y):

  drivers/infiniband/hw/bnxt_re/main.c:1114:2: error: unannotated fall-through between switch labels [-Werror,-Wimplicit-fallthrough]
   1114 |         default:
        |         ^
  drivers/infiniband/hw/bnxt_re/main.c:1114:2: note: insert 'break;' to avoid fall-through
   1114 |         default:
        |         ^
        |         break;
  1 error generated.

Clang is a little more pedantic than GCC, which does not warn when
falling through to a case that is just break or return. Clang's version
is more in line with the kernel's own stance in deprecated.rst, which
states that all switch/case blocks must end in either break,
fallthrough, continue, goto, or return. Add the missing break to silence
the warning.

Closes: https://github.com/ClangBuiltLinux/linux/issues/1950


Fixes: b02fd3f7 ("RDMA/bnxt_re: Report async events and errors")
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Link: https://lore.kernel.org/r/20231020-bnxt_re-implicit-fallthrough-v1-1-b5c19534a6c9@kernel.org


Signed-off-by: Leon Romanovsky <leon@kernel.org>