The output templates for zero_extendhidi2 and zero_extendqidi2 could
lead to incorrect code generation when zero-extending one register into
another. This patch adds a new output template to the define_insns to
handle such cases and produce correct asm.
gcc/ChangeLog:
* config/bpf/bpf.md (zero_extendhidi2): Add new output template
for register-to-register extensions.
(zero_extendqidi2): Likewise.