Build of lxc 3.2.1 fails with ultrasparc on:

raw_syscalls.c: In function ‘lxc_raw_clone’:
raw_syscalls.c:66:3: error: invalid 'asm': invalid operand output code
   asm volatile(
   ^~~

Issue has been added with commit
b52e8e68 which added %g1 instead of %%g1

Fixes:
 - http://autobuild.buildroot.org/results/17c2319850f02f24da6fbef9656c07f86fdc5a3aSigned-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>