kbuild, modpost: fix "unexpected non-allocatable" warning with SUSE gcc

Jean reported that he saw one warning for each module like the one below:
WARNING: arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.o (.comment.SUSE.OPTs): unexpected non-allocatable section.

The warning appeared with the improved version of the
check of the flags in the sections.

That check already ignored sections named ".comment" - but SUSE store
additional info in the comment section and has named it in a SUSE
specific way. Therefore modpost failed to ignore the section.

The fix is to extend the pattern so we ignore all sections
that start with the name ".comment.".

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Reported-by: Jean Delvare <khali@linux-fr.org>
Tested-by: Jean Delvare <khali@linux-fr.org>