lima/ppir: clone ld_{uni,tex,var} into each block

lima/ppir: clone ld_{uni,tex,var} into each block

ppir_lower_load() and ppir_lower_load_texture() assume that node
is in the same block as its successors, fix it by cloning each
ld_uni and ld_tex to every block.

It also reduces register pressure since values never cross block
boundaries and thus never appear in live_in or live_out of any block,
so do it for varyings as well.

Tested-by: Andreas Baierl <ichgeh@imkreisrum.de>
Reviewed-by: Qiang Yu <yuq825@gmail.com>
Reviewed-by: Erico Nunes <nunes.erico@gmail.com>
Signed-off-by: Vasily Khoruzhick <anarsoul@gmail.com>