x86/build: Remove unneeded uapi asm-generic wrappers

These are listed in include/uapi/asm-generic/Kbuild, so Kbuild will
automatically generate them.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20190723112646.14046-1-yamada.masahiro@socionext.com