generic: 5.15: add missing tag for some backports patches
Add for mtd-parsers-trx-allow-to-use-on-MediaTek-MIPS-SoCs.patch and
hwmon-lm70-Add-ti-tmp125-support.patch the 5.18 tag as it was merged
in kernel 5.18.
Signed-off-by: Christian Marangi <[email protected]>