MIPS: BPF: Add new emit_long_instr macro

This macro uses the capitalized UASM_* macros to emit 32 or 64-bit
instructions depending on the kernel configurations. This allows
us to remove a few CONFIG_64BIT ifdefs from the code.

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/7446/


Signed-off-by: Ralf Baechle <ralf@linux-mips.org>