sys/rump/librump/rumpkern/arch/i386/spinlock.c stop to build with DBG=-g

[Takehiko NOZAKI]

sys/rump/librump/rumpkern/arch/i386/spinlock.c stop to build with DBG=-g following message:

Error: bad register name `%sil'

[Takehiko NOZAKI]

famous gcc's bug, see following problem report:

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=35102

quick workaround use "q" instead of "r" to auto register assignment.

[Takehiko NOZAKI]

BUGFIX: Issue #103 - sys/rump/librump/rumpkern/arch/i386/spinlock.c stop to build with DBG=-g.

→ <<cset 7fcbafbbc1a1>>