kernel-doc: Fix symbol matching for dropped suffixes

kernel-doc: Fix symbol matching for dropped suffixes

The support for dropping "_noprof" missed dropping the suffix from
exported symbols.  That meant that using the :export: feature would
look for kernel-doc for (eg) krealloc_noprof() and not find the
kernel-doc for krealloc().

Fixes: 51a7bf0238c2 (scripts/kernel-doc: drop "_noprof" on function prototypes)
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20250606141543.1285671-1-willy@infradead.org