MIPS: math-emu: dsemul: Correct description of the emulation frame

MIPS: math-emu: dsemul: Correct description of the emulation frame

Remove irrelevant content from the description of the emulation frame in
`mips_dsemul', referring to bare-metal configurations.  Update the text,
reflecting the change made with commit ba3049ed4086 ("MIPS: Switch FPU
emulator trap to BREAK instruction."), where we switched from using an
address error exception on an unaligned access to the use of a BREAK 514
instruction causing a breakpoint exception instead.

Signed-off-by: Maciej W. Rozycki <macro@imgtec.com>
Cc: Aurelien Jarno <aurelien@aurel32.net>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/12176/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>