[PATCH] nvme: Increase block size variable size to 32-bit

[Christoph Hellwig]

> +	u32 bs = 1 << ns->lba_shift;

Make that 1 a 1U so that we're not going to run into sign extension
issues when using up all bits in the u32 :)

Otherwise looks good:

Reviewed-by: Christoph Hellwig <hch at lst.de>