common: cmd_bdinfo: fix type of value in print_lnum

This fixes a warning when compiling with ELDK-5.2.1 for MIPS64:

cmd_bdinfo.c: In function 'print_lnum':
cmd_bdinfo.c:56:2: warning: format '%llX' expects argument of type 'long long unsigned int', but argument 3 has type 'u64' [-Wformat]

Signed-off-by: Daniel Schwierzeck <daniel.schwierzeck@gmail.com>