qualcommax: add kernel cmdline replacement hack

qualcommax: add kernel cmdline replacement hack

Add kernel command line replacement hack to qualcommax. Now we can
find and replace arguments in the kernel command line by setting
bootargs-find-1, bootargs-replace-1, bootargs-exact-match-1
and bootargs-find-2, bootargs-replace-2, bootargs-exact-match-2
under the chosen node in the device tree.

This hack replaces the first occurence of bootargs-find-X with
bootargs-replace-X. When bootargs-exact-match-X is set to "y",
then the replacement happens only if the kernel command line is
identical to bootargs-find-X.

Signed-off-by: Qiyuan Zhang <zhang.github@outlook.com>
Link: https://github.com/openwrt/openwrt/pull/16070
Signed-off-by: Robert Marko <robimarko@gmail.com>