ARM: Fix inline assembly (r21949) for Clang.

Add a 'c' predicate to the immediate syscall number. This tells the
compiler to omit the leading '#' that immediates usually have in ARM.
The GNU assembler tolerates "ldr r7, =#1234" but Clang does not.

BUG=V8:3403
LOG=N
R=bmeurer@chromium.org

Review URL: https://codereview.chromium.org/356463004

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@21963 ce2b1a6d-e550-0410-aec6-3dcde31c8c00