* config/tc-mips.c (prev_insn_reloc_type): New static variable.
(RELAX_MIPS16_ENCODE): Add dslot and jal_dslot arguments, and
store them. Adjust other RELAX_MIPS16 macros.
(RELAX_MIPS16_DSLOT): Define.
(RELAX_MIPS16_JAL_DSLOT): Define.
(append_insn): Pass new arguments to RELAX_MIPS16_ENCODE. Correct
handling of whether previous instruction has a fixup. Set
prev_insn_reloc_type.
(mips_no_prev_insn): Clear prev_insn_reloc_type.
(mips16_extended_frag): Use the right base address for a PC
relative add or load.
(md_convert_frag): Likewise. If a PC relative add or load is
used, record the alignment for the section.