kbuild: check return value of asprintf()
kbuild: check return value of asprintf()

Check return value of asprintf() in docsect() and exit if error
occurs. This removes following warning:

  HOSTCC  scripts/basic/docproc
scripts/basic/docproc.c: In function ‘docsect’:
scripts/basic/docproc.c:336: warning: ignoring return value of ‘asprintf’,
				declared with attribute warn_unused_result

Signed-off-by: Namhyung Kim <5c915a589b3ddf58cebf14bec41bcc143b37ac3c@gmail.com>
Acked-by: Randy Dunlap <e1d10faa7e2a0c027bf1ff1d20e7fd10154be7ea@oracle.com>
Signed-off-by: Michal Marek <0c835876a532a476f30fdb1f6e963bae6c5a1a04@suse.cz>

KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas