x86/RAS/mce_amd_inj: Fix some W= warnings

x86/RAS/mce_amd_inj: Fix some W= warnings

In particular:

  arch/x86/ras/mce_amd_inj.c: In function ‘prepare_msrs’:
  arch/x86/ras/mce_amd_inj.c:249:13: warning: declaration of ‘i_mce’ shadows a global declaration [-Wshadow]
    struct mce i_mce = *(struct mce *)info;
               ^~~~~

  arch/x86/ras/mce_amd_inj.c: In function ‘init_mce_inject’:
  arch/x86/ras/mce_amd_inj.c:453:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
    for (i = 0; i < ARRAY_SIZE(dfs_fls); i++) {

Signed-off-by: Borislav Petkov <bp@suse.de>
Link: http://lkml.kernel.org/r/20160912075941.24699-16-bp@alien8.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>