Fixes for multi-architecture compilation

[manopapad]

The current code depends on one of FERMI_ARCH, KEPLER_ARCH, ... being defined

legate.pandas/src/pandas.cu

Line 27 in 7a97b45

#ifdef FERMI_ARCH

but if the core is build with support for multiple architectures then none of these will be defined:

https://github.com/nv-legate/legate.core/blob/branch-22.01/src/legate.mk#L90