x86/boot/e820: Remove a redundant self assignment

Remove a redundant self assignment of table->nr_entries, it does
nothing and is an artifact of code simplification re-work.

Detected by CoverityScan, CID#1428450 ("Self assignment")

Fixes: 441ac2f3

 ("x86/boot/e820: Simplify e820__update_table()")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Cc: kernel-janitors@vger.kernel.org
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Link: http://lkml.kernel.org/r/20170413155912.12078-1-colin.king@canonical.com


Signed-off-by: Thomas Gleixner <tglx@linutronix.de>