efivars: Fix check for CONFIG_EFI_VARS_PSTORE_DEFAULT_DISABLE
efivars: Fix check for CONFIG_EFI_VARS_PSTORE_DEFAULT_DISABLE

The 'CONFIG_' prefix is not implicit in IS_ENABLED().

Signed-off-by: Ben Hutchings <73675debcd8a436be48ec22211dcf44fe0df0a64@decadent.org.uk>
Cc: Seth Forshee <ead5052bef9b6b56b51f87cdc5b831be775ee6fb@canonical.com>
Cc: <4fbacc2fa0ffdbb11bf1ad6925b886ebd08dd15f@vger.kernel.org>
Signed-off-by: Matt Fleming <b02f0790d66a0f0a6b369873bf6df37420fbe5dd@intel.com>

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