[AMDGPU][GFX11] Fix dst register class for V_CVT_U32_U16

This instruction was referring to the wrong VOPProfile, likely due to a
typo, leading to an incorrect destination register type.

The MC layer will care about this change, but is NFC while 16-bit values
actually use 32 bit registers.

Reviewed By: foad

Differential Revision: https://reviews.llvm.org/D132878