x86: Remove unused patch_espfix_desc()

patch_espfix_desc() is not used after commit
dc4c2a0a

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
LKML-Reference: <20090718150955.GB11294@localhost.localdomain>
Signed-off-by: Ingo Molnar <mingo@elte.hu>