MIPS: Use proper kernel-doc Return keyword

For reference:
* https://www.kernel.org/doc/html/latest/doc-guide/kernel-doc.html#function-documentation

Fix non-fatal warning:

arch/mips/kernel/branch.c:418: warning: Excess function parameter 'returns' description in '__compute_return_epc_for_insn'

Signed-off-by: Mathieu Malaterre <[e-mail]>
Cc: Ralf Baechle <[e-mail]>
Cc: Randy Dunlap <[e-mail]>
Cc: Maciej W. Rozycki <[e-mail]>
Cc: Ingo Molnar <[e-mail]>
Cc: Paul Burton <[e-mail]>
Cc: [e-mail]
Patchwork: https://patchwork.linux-mips.org/patch/18031/
[[e-mail]: Expand subject slightly]
Signed-off-by: James Hogan <[e-mail]>

arch/mips/kernel/branch.c

···
  *
  * @regs:	Pointer to pt_regs
  * @insn:	branch instruction to decode
- * @returns:	-EFAULT on error and forces SIGILL, and on success
+ * Return:	-EFAULT on error and forces SIGILL, and on success
  *		returns 0 or BRANCH_LIKELY_TAKEN as appropriate after
  *		evaluating the branch.
  *