Yes, you can uplink your 2248 to both 5548s. Have a look at this link for example and explanation:
you need NX-OS 5.1(3)N1(1) or later: You can also uplink your server to one or both FEXs.
It was told to me that now, as of a fairly recent NX-OS release, you can have the 2248 going dual-homed to both 5548 via VPC and then have a server connected to both 2248 and be in active-active mode. Is this correct?
In THEORY, this is possible.
In PRACTICE, dual homing of a FEX to two 5000/5500 is best avoided. A mis-configuration can cause the Nexus 5K to have a split brain (worst case scenario).
In practice, it's best to single-home the FEX to a single Nexus 5K. It is also recommendable to vPC the links to-and-from the 5K and 2K.