compiler-gcc.h: use "proved" instead of "proofed"

Link: http://lkml.kernel.org/r/1477894241.1103202.772260161.1B0A5995@webmail.messagingengine.com
Signed-off-by: Benjamin Peterson <bp@benjamin.pe>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/linux/compiler-gcc.h

@@ -21,7 +21,7 @@
  * clobbered. The issue is as follows: while the inline asm might
  * access any memory it wants, the compiler could have fit all of
  * @ptr into memory registers instead, and since @ptr never escaped
- * from that, it proofed that the inline asm wasn't touching any of
+ * from that, it proved that the inline asm wasn't touching any of
  * it. This version works well with both compilers, i.e. we're telling
  * the compiler that the inline asm absolutely may see the contents
  * of @ptr. See also: https://llvm.org/bugs/show_bug.cgi?id=15495