poly1305: fix compilation on arm with go tip

Fix compilation of poly1305 using go tip - it currently fails with:

./poly1305_arm.s:124: cannot reference SP without a symbol
./poly1305_arm.s:161: cannot reference SP without a symbol
./poly1305_arm.s:162: cannot reference SP without a symbol
asm: asm: assembly of ./poly1305_arm.s failed

Change-Id: I797dcf3641cc881b6cc192034b693ccf58317987
Reviewed-on: https://go-review.googlesource.com/10307
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Adam Langley <agl@golang.org>
1 file changed