Fix compilation with GCC-8

Fix compilation with GCC-8

Printf() is being called to print an unsigned long int using the long long
identifier. This causes the following error with GCC-8:

	nvme.c:3056:5: error: format ‘%llu’ expects argument of type ‘long long unsigned int’, but argument 3 has type ‘__u64 {aka long unsigned int}’ [-Werror=format=]
	     "Invalid value for block size (%llu), must be a power of two\n",
	     ^
	nvme.c:3091:6: error: format ‘%llu’ expects argument of type ‘long long unsigned int’, but argument 3 has type ‘__u64 {aka long unsigned int}’ [-Werror=format=]
	      "LBAF corresponding to block size %llu (LBAF %u) not found\n",

Adjusting the printf arguments to print the proper format.

Signed-off-by: Breno Leitao <leitao@debian.org>