meta-agl-profile-core: update most recipe

meta-agl-profile-core: update most recipe

Update SRCREV in MOST driver recipe to pick up:

e4dbbaf sound.c: Remove snd_pcm_lib_mmap_vmalloc

As well, the following changes have been made to the bbappend:
- the kernel version detection logic has been removed
- the patch to support kernels older than 4.13 has been removed
- the patch that was handling the snd_pcm_lib_mmap_vmalloc issue on
  kernels >= 4.19 has been reworked to add the required #ifdefs to
  support kernels < 4.19 for e.g. the rcar3 4.14-ltsi kernel.

Bug-AGL: SPEC-2932

Change-Id: I388d186d04ccc017ff10b2024ae35ed22f7a8e36
Signed-off-by: Scott Murray <scott.murray@konsulko.com>