bug in mips64 get_top_frame (profile.h)

["Chris Thomson" <cmt@xxxxxxxxx>]

I've been hacking at a PowerPC port of kernprof, and while
studying the existing versions, spotted what appears to be
a bug in the MIPS64 version.

In asm-mips64/profile.h, there's a function get_top_frame
that scans for a daddiu $sp,$sp,... instruction, and then
for a jr $ra instruction.  If it finds the jr $ra, it should
return, but continues to loop.  This would cause it to scan
back to the previous function instead of using the current
one...