main/linux-postmarketos-qcom-msm8916: upgrade to 5.7-rc2

For main/linux-postmarketos-qcom-msm8916:

• Update to Linux 5.7-rc2
• Initial support for BQ Aquaris X5 (bq-paella/picmt) (contributed by @lazzardo)
• Add speaker for samsung-gt510wifi/matissevewifi (contributed by @Minecrell, @jja2000 and @rvlander)
• Add flash LED for wileyfox-crackling (contributed by @TravMurav, with driver from @z3ntu)

For device/testing/soc-qcom-msm8916:

• Enable speaker on samsung-gt510wifi/matissevewifi
• Replace deprecated mesa-dri-freedreno package with mesa-dri-gallium
• Build natively (this is just a trivial copy)

Cc: @Mis012 @TravMurav @jja2000 @srxl @rvlander @lazzardo @minlexx