mac80211: brcmfmac: rename 4.20 backport patches

Include kernel version to help tracking changes.

Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
(cherry picked from commit f7a3459ab9c4d8f5102c8ae0861ca481571703f7)

diff --git a/package/kernel/mac80211/patches/342-0001-brcmfmac-add-CYW89342-mini-PCIe-device.patch b/package/kernel/mac80211/patches/342-v4.20-0001-brcmfmac-add-CYW89342-mini-PCIe-device.patch
similarity index 100%
rename from package/kernel/mac80211/patches/342-0001-brcmfmac-add-CYW89342-mini-PCIe-device.patch
rename to package/kernel/mac80211/patches/342-v4.20-0001-brcmfmac-add-CYW89342-mini-PCIe-device.patch

diff --git a/package/kernel/mac80211/patches/344-0001-brcmfmac-fix-wrong-strnchr-usage.patch b/package/kernel/mac80211/patches/344-v4.20-0001-brcmfmac-fix-wrong-strnchr-usage.patch
similarity index 100%
rename from package/kernel/mac80211/patches/344-0001-brcmfmac-fix-wrong-strnchr-usage.patch
rename to package/kernel/mac80211/patches/344-v4.20-0001-brcmfmac-fix-wrong-strnchr-usage.patch

diff --git a/package/kernel/mac80211/patches/345-0001-brcmfmac-fix-for-proper-support-of-160MHz-bandwidth.patch b/package/kernel/mac80211/patches/345-v4.20-0001-brcmfmac-fix-for-proper-support-of-160MHz-bandwidth.patch
similarity index 100%
rename from package/kernel/mac80211/patches/345-0001-brcmfmac-fix-for-proper-support-of-160MHz-bandwidth.patch
rename to package/kernel/mac80211/patches/345-v4.20-0001-brcmfmac-fix-for-proper-support-of-160MHz-bandwidth.patch

diff --git a/package/kernel/mac80211/patches/345-0002-brcmfmac-increase-buffer-for-obtaining-firmware-capa.patch b/package/kernel/mac80211/patches/345-v4.20-0002-brcmfmac-increase-buffer-for-obtaining-firmware-capa.patch
similarity index 100%
rename from package/kernel/mac80211/patches/345-0002-brcmfmac-increase-buffer-for-obtaining-firmware-capa.patch
rename to package/kernel/mac80211/patches/345-v4.20-0002-brcmfmac-increase-buffer-for-obtaining-firmware-capa.patch