lima/ppir: fix codegen const bitcopy size

pp consts are embedded as vec4 in pp instructions and unconditionally take 64 bits when enabled in the control word (4 half floats). ppir handles and generates the half float vector correctly, but during the final copy of data to the instruction, was using an expression to calculate the size which resulted in less than the 64 bits, so the consts would not be effectively copied to the final instruction. This fixes ppir codegen to just copy the 64 bits.

Signed-off-by: Erico Nunes nunes.erico@gmail.com