staging: r8188eu: do not write past the end of an array

staging: r8188eu: do not write past the end of an array

Commit f7b687d6b67e ("staging: r8188eu: remove NumTotalRFPath from struct
hal_data_8188e") removed a for loop around a block of code that is executed
only once when i == 0. However, without the for loop, i will never be set
to 0 before the code block is executed. i remains at 2, which is the final
value after the previous loop. This results in a write past the end of the
powerlevel and MCSBase arrays.

[   28.480809] Kernel panic - not syncing: stack-protector: Kernel stack is corrupted in: rtl8188e_PHY_RF6052SetOFDMTxPower+0x124/0x128 [r8188eu]
[   28.493752] ---[ end Kernel panic - not syncing: stack-protector: Kernel stack is corrupted in: rtl8188e_PHY_RF6052SetOFDMTxPower+0x124/0x128 [r8188eu] ]---

Fix this by replacing i with 0 in the code block that used to be the body of
the loop. While at it, remove the powerlevel array that was just holding a
temporary value.

Tested with Edimax EW-7811Un V2 on an ARM32 embedded system.

Fixes: f7b687d6b67e ("staging: r8188eu: remove NumTotalRFPath from struct hal_data_8188e")
Acked-by: Michael Straube <straube.linux@gmail.com>
Signed-off-by: Martin Kaiser <martin@kaiser.cx>
Link: https://lore.kernel.org/r/20210918134024.23837-1-martin@kaiser.cx
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>