meson: disable oe-sdk by default

The meson option oe-sdk is used in rare scenarios.  Having it
non-defaulted turns it into an `auto` feature, which is not desired.
Explicitly disable it by default.

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: I975964a1c316438e9ee358b84ff1b9a5c72de763
diff --git a/meson.options b/meson.options
index 5e87c44..2d17003 100644
--- a/meson.options
+++ b/meson.options
@@ -1,5 +1,5 @@
 option('tests', type: 'feature', description: 'Build tests.')
-option('oe-sdk', type: 'feature', description: 'Enable OE SDK')
+option('oe-sdk', type: 'feature', value: 'disabled', description: 'Enable OE SDK')
 option('device-type', type: 'combo', choices: ['static', 'ubi', 'mmc'], description: 'Select which device type to support')
 option('vpnor', type: 'feature', description: 'Enable virtual PNOR support')
 option('pldm', type: 'feature', description: 'Enable Host PLDM support')