hwclock: don't ifdef printf arguments

hwclock: don't ifdef printf arguments

This may fails if printf() is macro, introduced in cc7cb070.

clang compiler warnings:

    CC       sys-utils/hwclock.o
  ../sys-utils/hwclock.c:1228:2: warning: embedding a directive within macro arguments has undefined behavior [-Wembedded-directive]
  #ifdef __linux__
   ^
  ../sys-utils/hwclock.c:1230:2: warning: embedding a directive within macro arguments has undefined behavior [-Wembedded-directive]
  #endif
   ^
  2 warnings generated.

CC: J William Piggott <elseifthen@gmx.com>
Signed-off-by: Ruediger Meier <ruediger.meier@ga-group.nl>